15 Language Corpora

內容

The term language corpus is used to mean a number of rather different things. It may refer simply to any collection of linguistic data (for example, written, spoken, signed, or multimodal), although many practitioners prefer to reserve it for collections which have been organized or collected with a particular end in view, generally to characterize a particular state or variety of one or more languages. Because opinions as to the best method of achieving this goal differ, various subcategories of corpora have also been identified. For our purposes however, the distinguishing characteristic of a corpus is that its components have been selected or structured according to some conscious set of design criteria.

These design criteria may be very simple and undemanding, or very sophisticated. A corpus may be intended to represent (in the statistical sense) a particular linguistic variety or sublanguage, or it may be intended to represent all aspects of some assumed ‘core’ language. A corpus may be made up of whole texts or of fragments or text samples. It may be a ‘closed’ corpus, or an ‘open’ or ‘monitor’ corpus, the composition of which may change over time. However, since an open corpus is of necessity finite at any particular point in time, the only likely effect of its expansibility from the encoding point of view may be some increased difficulty in maintaining consistent encoding practices (see further section 15.5 Recommendations for the Encoding of Large Corpora). For simplicity, therefore, our discussion largely concerns ways of encoding closed corpora, regarded as single but composite texts.

Language corpora are regarded by these Guidelines as composite texts rather than unitary texts (on this distinction, see chapter 4 Default Text Structure). This is because although each discrete sample of language in a corpus clearly has a claim to be considered as a text in its own right, it is also regarded as a subdivision of some larger object, if only for convenience of analysis. Corpora share a number of characteristics with other types of composite texts, including anthologies and collections. Most notably, different components of composite texts may exhibit different structural properties (for example, some may be composed of verse, and others of prose), thus potentially requiring elements from different TEI modules.

Aside from these high-level structural differences, and possibly differences of scale, the encoding of language corpora and the encoding of individual texts present identical sets of problems. Any of the encoding techniques and elements presented in other chapters of these Guidelines may therefore prove relevant to some aspect of corpus encoding and may be used in corpora. Therefore, we do not repeat here the discusssion of such fundamental matters as the representation of multiple character sets (see chapter vi. Languages and Character Sets); nor do we attempt to summarize the variety of elements provided for encoding basic structural features such as quoted or highlighted phrases, cross-references, lists, notes, editorial changes and reference systems (see chapter 3 Elements Available in All TEI Documents). In addition to these general purpose elements, these Guidelines offer a range of more specialized sets of tags which may be of use in certain specialized corpora, for example those consisting primarily of verse (chapter 6 Verse), drama (chapter 7 Performance Texts), transcriptions of spoken text (chapter 8 Transcriptions of Speech), etc. Chapter 1 The TEI Infrastructure should be reviewed for details of how these and other components of the Guidelines should be tailored to create a document type definition appropriate to a given application. In sum, it should not be asssumed that only the matters specifically addressed in this chapter are of importance for corpus creators.

This chapter does however include some other material relevant to corpora and corpus-building, for which no other location appeared suitable. It begins with a review of the distinction between unitary and composite texts, and of the different methods provided by these Guidelines for representing composite texts of different kinds (section 15.1 Varieties of Composite Text). Section 15.2 Contextual Information describes a set of additional header elements provided for the documentation of contextual information, of importance largely though not exclusively to language corpora. This is the additional module for language corpora proper. Section 15.3 Associating Contextual Information with a Text discusses a mechanism by which individual parts of the TEI Header may be associated with different parts of a TEI-conformant text. Section 15.4 Linguistic Annotation of Corpora reviews various methods of providing linguistic annotation in corpora, with some specific examples of relevance to current practice in corpus linguistics. Finally, section 15.5 Recommendations for the Encoding of Large Corpora provides some general recommendations about the use of these Guidelines in the building of large corpora.

15.1 Varieties of Composite Text

Both unitary and composite texts may be encoded using these Guidelines; composite texts, including corpora, will typically make use of the following tags for their top-level organization.
  • teiCorpus 包含一套用TEI編碼的文件集，由單一文集標頭以及一個 (或多個) TEI元素所組成，各TEI元素包含單一文本標頭和一個文本。
  • TEI (TEI文件) 包含符合TEI標準的單一文件，由一個TEI標頭及一份文本組成，可單獨出現或是作為元素teiCorpus的一部分。
  • teiHeader (TEI標頭) 在所有符合TEI標準的文本起始的電子題名頁當中提供敘述性以及宣告性的資訊。
    type標明標頭所附屬於的文件類型，例如文集或單一文本。
  • text 包含一份任何種類的文本，無論是單一或複合的，例如詩詞或戲劇、散文集、小說、字典、或是文集範例。
  • group 包含複合文本的正文，所匯集的一連串單一文件 (或文件群組) ，因為某特殊目的被視為一個整體，例如一個作者的作品集合、一連串的散文集等。
Full descriptions of these may be found in chapter 2 The TEI Header (for teiHeader), and chapter 4 Default Text Structure (for teiCorpus TEI, text and group); this section discusses their application to composite texts in particular.
In these Guidelines, the word text refers to any stretch of discourse, whether complete or incomplete, unitary or composite, which the encoder chooses (perhaps merely for purposes of analytic convenience) to regard as a unit. The term composite text refers to texts within which other texts appear; the following common cases may be distinguished:
  • language corpora
  • collections or anthologies
  • poem cycles and epistolary works (novels or essays written in the form of collections or series of letters)
  • otherwise unitary texts, within which one or more subordinate texts are embedded
The elements listed above may be combined to encode each of these varieties of composite text in different ways.

In corpora, the component samples are clearly distinct texts, but the systematic collection, standardized preparation, and common markup of the corpus often make it useful to treat the entire corpus as a unit, too. Some corpora may become so well established as to be regarded as texts in their own right; the Brown and LOB corpora are now close to achieving this status.

The teiCorpus element is intended for the encoding of language corpora, though it may also be useful in encoding newspapers, electronic anthologies, and other disparate collections of material. The individual samples in the corpus are encoded as separate TEI elements, and the entire corpus is enclosed in a teiCorpus element. Each sample has the usual structure for a TEI document, comprising a teiHeader followed by a text element. The corpus, too, has a corpus-level teiHeader element, in which the corpus as a whole, and encoding practices common to multiple samples may be described. The overall structure of a TEI-conformant corpus is thus:
<teiCorpus>
 <teiHeader type="corpus"/>
 <TEI>
  <teiHeader type="text"/>
  <text/>
 </TEI>
 <TEI>
  <teiHeader type="text"/>
  <text/>
 </TEI>
</teiCorpus>

Header information which relates to the whole corpus rather than to individual components of it should be factored out and included in the teiHeader element prefixed to the whole. This two-level structure allows for contextual information to be specified at the corpus level, at the individual text level, or at both. Discussion of the kinds of information which may thus be specified is provided below, in section 15.2 Contextual Information, as well as in chapter 2 The TEI Header. Information of this type should in general be specified only once: a variety of methods are provided for associating it with individual components of a corpus, as further described in section 15.3 Associating Contextual Information with a Text.

In some cases, the design of a corpus is reflected in its internal structure. For example, a corpus of newspaper extracts might be arranged to combine all stories of one type (reportage, editorial, reviews, etc.) into some higher-level grouping, possibly with sub-groups for date, region, etc. The teiCorpus element provides no direct support for reflecting such internal corpus structure in the markup: it treats the corpus as an undifferentiated series of components, each tagged TEI.

If it is essential to reflect a single permanent organization of a corpus into sub- and sub-sub-corpora, then the corpus or the high-level subcorpora may be encoded as composite texts, using the group element described below and in section 4.3.1 Grouped Texts. The mechanisms for corpus characterization described in this chapter, however, are designed to reduce the need to do this. Useful groupings of components may easily be expressed using the text classification and identification elements described in section 15.2.1 The Text Description, and those for associating declarations with corpus components described in section 15.3 Associating Contextual Information with a Text. These methods also allow several different methods of text grouping to co-exist, each to be used as needed at different times. This helps minimize the danger of cross-classification and mis-classification of samples, and helps improve the flexibility with which parts of a corpus may be characterized for different applications.

Anthologies and collections are often treated as texts in their own right, if only for historical reasons. In conventional publishing, at least, anthologies are published as units, with single editorial responsibility and common front and back matter which may need to be included in their electronic encodings. The texts collected in the anthology, of course, may also need to be identifiable as distinct individual objects for study.

Poem cycles, epistolary novels, and epistolary essays differ from anthologies in that they are often written as single works, by single authors, for single occasions; nevertheless, it can be useful to treat their constituent parts as individual texts, as well as the cycle itself. Structurally, therefore, they may be treated in the same way as anthologies: in both cases, the body of the text is composed largely of other texts.

The group element is provided to simplify the encoding of collections, anthologies, and cyclic works; as noted above, the group element can also be used to record the potentially complex internal structure of language corpora. For a full description, see chapter 4 Default Text Structure.

Some composite texts, finally, are neither corpora, nor anthologies, nor cyclic works: they are otherwise unitary texts within which other texts are embedded. In general, they may be treated in the same way as unitary texts, using the normal TEI and body elements. The embedded text itself may be encoded using the text element, which may occur within quotations or between paragraphs or other chunk-level elements inside the sections of a larger text. For further discussion, see chapter 4 Default Text Structure.

All composite texts share the characteristic that their different component texts may be of structurally similar or dissimilar types. If all component texts may all be encoded using the same module, then no problem arises. If however they require different modules, then these must be included in the schema. This process is described in more detail in section 1.1 TEI Modules.

15.2 Contextual Information

Contextual information is of particular importance for collections or corpora composed of samples from a variety of different kinds of text. Examples of such contextual information include: the age, sex, and geographical origins of participants in a language interaction, or their socio-economic status; the cost and publication data of a newspaper; the topic, register or factuality of an extract from a textbook. Such information may be of the first importance, whether as an organizing principle in creating a corpus (for example, to ensure that the range of values in such a parameter is evenly represented throughout the corpus, or represented proportionately to the population being sampled), or as a selection criterion in analysing the corpus (for example, to investigate the language usage of some particular vector of social characteristics).

Such contextual information is potentially of equal importance for unitary texts, and these Guidelines accordingly make no particular distinction between the kinds of information which should be gathered for unitary and for composite texts. In either case, the information should be recorded in the appropriate section of a TEI Header, as described in chapter 2 The TEI Header. In the case of language corpora, such information may be gathered together in the overall corpus header, or split across all the component texts of a corpus, in their individual headers, or divided between the two. The association between an individual corpus text and the contextual information applicable to it may be made in a number of ways, as further discussed in section 15.3 Associating Contextual Information with a Text below.

Chapter 2 The TEI Header, which should be read in conjunction with the present section, describes in full the range of elements available for the encoding of information relating to the electronic file itself, for example its bibliographic description and those of the source or sources from which it was derived (see section 2.2 The File Description); information about the encoding practices followed with the corpus, for example its design principles, editorial practices, reference system, etc. (see section 2.3 The Encoding Description); more detailed descriptive information about the creation and content of the corpus, such as the languages used within it and any descriptive classification system used (see section 2.4 The Profile Description); and version information documenting any changes made in the electronic text (see section 2.5 The Revision Description).

In addition to the elements defined by chapter 2 The TEI Header, several other elements can be used in the TEI header if the additional module defined by this chapter is invoked. These additional tags make it possible to characterize the social or other situation within which a language interaction takes place or is experienced, the physical setting of a language interaction, and the participants in it. Though this information may be relevant to, and provided for, unitary texts as well as for collections or corpora, it is more often recorded for the components of systematically developed corpora than for isolated texts, and thus this module is referred to as being ‘for language corpora’.

When the module defined in this chapter is included in a schema, a number of additional elements become available within the profileDesc element of the TEI Header (discussed in section 2.4 The Profile Description).
  • textDesc (文本描述) 提供文本在情境特徵方面的相關描述。
  • particDesc (參與描述) 描述在一個語言互動中可辨識的說話者、聲音或其他參與者。
  • settingDesc (背景描述) 描述語言互動所發生的一個或多個背景，可用一段散文描述或是一系列的背景元素來表達。
These elements, members of the model.profileDescPart, are discussed in the remainder of the chapter.

15.2.1 The Text Description

The textDesc element provides a full description of the situation within which a text was produced or experienced, and thus characterizes it in a way relatively independent of any a priori theory of text-types. It is provided as an alternative or a supplement to the common use of descriptive taxonomies used to categorize texts, which is fully described in section 2.4.3 The Text Classification, and section 2.3.6 The Classification Declaration. The description is organized as a set of values and optional prose descriptions for the following eight situational parameters, each represented by one of the following eight elements:
  • channel (主要途徑) 描述文本傳達的媒介或途徑。書面文本的途徑可能是印製、手稿、寫本、電子郵件等；口說文本則有廣播、電話、面對面交談等。
    mode說明該途徑為口說或書面模式。
  • constitution 描述文本或文本樣本的內部結構，例如零碎的或完整的結構。
    type說明文本構成方式。
  • derivation 描述文本的特性與原創性的程度。
    type將文本來歷分類。
  • domain (應用領域) 描述該文本最重要的應用領域或是社會用途所在，例如私人與公共、教育、宗教等。
    type將應用領域分類。
  • factuality 描述該文本內容可能被認定為想像的程度、所描繪的為虛構或真實的世界。
    type將文本的真實性分類。
  • interaction 描述文本創作者與體驗者之間互動關係的規範、基數和特性，例如回應或感嘆、評論等。
    type說明文本中主動與被動參與者之間的互動程度。
    active說明創作文本部份內容的主動參與者 (或傳達者) 的人數。
    passive說明文本內容的被動參與者 (或接收者) 的人數，被動參與者即為文本產生或呈現的對象。
  • preparedness 描述文本可能被視為經過準備或自然呈現的程度。
    type說明準備程度的類型。
  • purpose 描述該文本的一項目的或溝通功能
    type說明一項特定類型的目的。
    degree說明該目的所佔的重要性程度。

These elements constitute a model class called model.textDescPart; new parameters may be defined by defining new elements and adding them to that class, as further described in 23.2 Personalization and Customization.

By default, a text description will contain each of the above elements, supplied in the order specified. Except for the purpose element, which may be repeated to indicate multiple purposes, no element should appear more than once within a single text description. Each element may be empty, or may contain a brief qualification or more detailed description of the value expressed by its attributes. It should be noted that some texts, in particular literary ones, may resist unambiguous classification in some of these dimensions; in such cases, the situational parameter in question should be given the content ‘not applicable’ or an equivalent phrase.

Texts may be described along many dimensions, according to many different taxonomies. No generally accepted consensus as to how such taxonomies should be defined has yet emerged, despite the best efforts of many corpus linguists, text linguists, sociolinguists, rhetoricians, and literary theorists over the years. Rather than attempting the task of proposing a single taxonomy of text-types (or the equally impossible one of enumerating all those which have been proposed previously), the closed set of situational parameters described above can be used in combination to supply useful distinguishing descriptive features of individual texts, without insisting on a system of discrete high-level text-types. Such text-types may however be used in combination with the parameters proposed here, with the advantage that the internal structure of each such text-type can be specified in terms of the parameters proposed. This approach has the following analytical advantages:45
  • it enables a relatively continuous characterization of texts (in contrast to discrete categories based on type or topic)
  • it enables meaningful comparisons across corpora
  • it allows analysts to build and compare their own text-types based on the particular parameters of interest to them
  • it is equally applicable to spoken, written, or signed texts

Two alternative approaches to the use of these parameters are supported by these Guidelines. One is to use pre-existing taxonomies such as those used in subject classification or other types of text categorization. Such taxonomies may also be appropriate for the description of the topics addressed by particular texts. Elements for this purpose are described in section 2.4.3 The Text Classification, and elements for defining or declaring such classification schemes in section 2.3.6 The Classification Declaration. A second approach is to develop an application-specific set of feature structures and an associated feature system declaration, as described in chapters 18 Feature Structures and 18.11 Feature System Declaration.

Where the organizing principles of a corpus or collection so permit, it may be convenient to regard a particular set of values for the situational parameters listed in this section as forming a text-type in its own right; this may also be useful where the same set of values applies to several texts within a corpus. In such a case, the set of text-types so defined should be regarded as a taxonomy. The mechanisms described in section 2.3.6 The Classification Declaration may be used to define hierarchic taxonomies of such text-types, provided that the catDesc component of the category element contains a textDesc element rather than a prose description. Particular texts may then be associated with such definitions using the mechanisms described in sections 2.4.3 The Text Classification.

Using these situational parameters, an informal domestic conversation might be characterized as follows:
<textDesc n="Informal domestic conversation">
 <channel mode="s">informal face-to-face conversation</channel>
 <constitution type="single">each text represents a continuously
   recorded interaction among the specified participants
 </constitution>
 <derivation type="original"/>
 <domain type="domestic">plans for coming week, local affairs</domain>
 <factuality type="mixed">mostly factual, some jokes</factuality>
 <interaction type="complete" active="plural" passive="many"/>
 <preparedness type="spontaneous"/>
 <purpose type="entertain" degree="high"/>
 <purpose type="inform" degree="medium"/>
</textDesc>
The following example demonstrates how the same situational parameters might be used to characterize a novel:
<textDesc n="novel">
 <channel mode="w">print; part issues</channel>
 <constitution type="single"/>
 <derivation type="original"/>
 <domain type="art"/>
 <factuality type="fiction"/>
 <interaction type="none"/>
 <preparedness type="prepared"/>
 <purpose type="entertain" degree="high"/>
 <purpose type="inform" degree="medium"/>
</textDesc>

15.2.2 The Participant Description

The particDesc element in the profileDesc element provides additional information about the participants in a spoken text or, where this is judged appropriate, the persons named or depicted in a written text. When the detailed elements provided by the namesdates module described in 13 Names, Dates, People, and Places are included in a schema, this element can contain detailed demographic or descriptive information about individual speakers or groups of speakers, such as their names or other personal characteristics. Individually identified persons may also identified by a code which can then be used elsewhere within the encoded text, for example as the value of a who attribute.

It should be noted that although the terms speaker or participant are used throughout this section, it is intended that the same mechanisms may be used to characterize fictional personæ or ‘voices’ within a written text, except where otherwise stated. For the purposes of analysis of language usage, the information specified here should be equally applicable to written, spoken, or signed texts.

The element particDesc contains a description of the participants in an interaction, which may be supplied as straightforward prose, possibly containing a list of names, encoded using the usual list and name elements, or alternatively using the more specific and detailed listPerson element provided by the namesdates module described in 13 Names, Dates, People, and Places.

For example, a participant in a recorded conversation might be described informally as follows:
<particDesc xml:id="p2">
 <p>Female informant, well-educated, born in Shropshire UK, 12 Jan
   1950, of unknown occupation. Speaks French fluently.
   Socio-Economic status B2 in the PEP classification scheme.</p>
</particDesc>
Alternatively, when the namesdates module is included in a schema, information about the same participant described above might be provided in a more structured way as follows:
<person sex="2" age="mid">
 <birth when="1950-01-12">
  <date>12 Jan 1950</date>
  <name type="place">Shropshire, UK</name>
 </birth>
 <langKnowledge tags="en fr">
  <langKnown level="first" tag="en">English</langKnown>
  <langKnown tag="fr">French</langKnown>
 </langKnowledge>
 <residence>Long term resident of Hull</residence>
 <education>University postgraduate</education>
 <occupation>Unknown</occupation>
 <socecStatus scheme="#pep" code="#b2"/>
</person>
An identified character in a drama or a novel may also be regarded as a participant in this sense, and encoding using the same techniques:46
<particDesc>
 <p>The chief speaking characters in this novel are
 <list>
   <item xml:id="EMWOO">
    <name>Emma Woodhouse</name>
   </item>
   <item xml:id="DARCY">
    <name>Mr Darcy</name>
   </item>
<!-- ... -->
  </list>
 </p>
</particDesc>
Here, the characters are simply listed without the detailed structure which use of the listPerson element permits.

15.2.3 The Setting Description

The settingDesc element is used to describe the setting or settings in which language interaction takes place. It may contain a prose description, analogous to a stage description at the start of a play, stating in broad terms the locale, or a more detailed description of a series of such settings.

Each distinct setting is described by means of a setting element.
  • setting 描述語言互動發生的一個特定背景。
Individual settings may be associated with particular participants by means of the optional who attribute which this element inherits as a member of the att.ascribed if, for example, participants are in different places. This attribute identifies one or more individual participants or participant groups, as discussed earlier in section 15.2.2 The Participant Description. If this attribute is not specified, the setting details provided are assumed to apply to all participants represented in the language interaction. Note however that it is not possible to encode different settings for the same participant: a participant is deemed to be a person within a specific setting.
The setting element may contain either a prose description or a selection of elements from the classes model.nameLike.agent, model.dateLike, or model.settingPart. By default, when the module definded by this chapter is included in a schema, these classes thus provide the following elements :
  • name (名稱，特定名稱) 包含一個特定名稱 或名詞詞組。
  • date 包含任何格式的日期表示。
  • time 包含一組字詞，以任何形式定義時間
  • locale 包含簡短非正式的文字描述地點的性質，例如房間、餐廳、公園長椅等。
  • activity 包含簡短非正式的文字，描述一個對話參與者除了說話以外其他可能的動作。
Additional more specific naming elements such as orgName or persName may also be available if the namesdates module is also included in the schema.
The following example demonstrates the kind of background information often required to support transcriptions of language interactions, first encoded as a simple prose narrative:
<settingDesc>
 <p>The time is early spring, 1989. P1 and P2 are playing on the rug
   of a suburban home in Bedford. P3 is doing the washing up at the
   sink. P4 (a radio announcer) is in a broadcasting studio in
   London.</p>
</settingDesc>
The same information might be represented more formally in the following way:
<settingDesc>
 <setting who="#p1 #p2">
  <name type="city">Bedford</name>
  <name type="region">UK: South East</name>
  <date>early spring, 1989</date>
  <locale>rug of a suburban home</locale>
  <activity>playing</activity>
 </setting>
 <setting who="#p3">
  <name type="city">Bedford</name>
  <name type="region">UK: South East</name>
  <date>early spring, 1989</date>
  <locale>at the sink</locale>
  <activity>washing-up</activity>
 </setting>
 <setting who="#p4">
  <name type="place">London, UK</name>
  <time>unknown</time>
  <locale>broadcasting studio</locale>
  <activity>radio performance</activity>
 </setting>
</settingDesc>
Again, a more detailed encoding for places is feasible if the namesdates module is included in the schema. The above examples assume that only the general purpose name element supplied in the core module is available.

15.3 Associating Contextual Information with a Text

This section discusses the association of the contextual information held in the header with the individual elements making up a TEI text or corpus. Contextual information is held in elements of various kinds within the TEI header, as discussed elsewhere in this section and in chapter 2 The TEI Header. Here we consider what happens when different parts of a document need to be associated with different contextual information of the same type, for example when one part of a document uses a different encoding practice from another, or where one part relates to a different setting from another. In such situations, there will be more than one instance of a header element of the relevant type.

The TEI scheme allow for the following possibilities:
  • A given element may appear in the corpus header only, in the header of one or more texts only, or in both places
  • There may be multiple occurrences of certain elements in either corpus or text header.

To simplify the exposition, we deal with these two possibilities separately in what follows; however, they may be combined as desired.

15.3.1 Combining Corpus and Text Headers

A TEI-conformant document may have more than one header only in the case of a TEI corpus, which must have a header in its own right, as well as the obligatory header for each text. Every element specified in a corpus-header is understood as if it appeared within every text header in the corpus. An element specified in a text header but not in the corpus header supplements the specification for that text alone. If any element is specified in both corpus and text headers, the corpus header element is over-ridden for that text alone.

The titleStmt for a corpus text is understood to be prefixed by the titleStmt given in the corpus header. All other optional elements of the fileDesc should be omitted from an individual corpus text header unless they differ from those specified in the corpus header. All other header elements behave identically, in the manner documented below. This facility makes it possible to state once for all in the corpus header each piece of contextual information which is common to the whole of the corpus, while still allowing for individual texts to vary from this common denominator.

For example, the following schematic shows the structure of a corpus comprising three texts, the first and last of which share the same encoding description. The second one has its own encoding description.
<teiCorpus>
 <teiHeader>
  <fileDesc>
<!-- corpus file description-->
  </fileDesc>
  <encodingDesc>
<!-- default encoding description -->
  </encodingDesc>
  <revisionDesc>
<!-- corpus revision description -->
  </revisionDesc>
 </teiHeader>
 <TEI>
  <teiHeader>
   <fileDesc>
<!-- file description for this corpus text -->
   </fileDesc>
  </teiHeader>
  <text>
<!-- first corpus text -->
  </text>
 </TEI>
 <TEI>
  <teiHeader>
   <fileDesc>
<!-- file description for this corpus text -->
   </fileDesc>
   <encodingDesc>
<!-- encoding description for this corpus text, over-riding the default -->
   </encodingDesc>
  </teiHeader>
  <text>
<!-- second corpus text -->
  </text>
 </TEI>
 <TEI>
  <teiHeader>
   <fileDesc>
<!-- file description for third corpus text -->
   </fileDesc>
  </teiHeader>
  <text>
<!-- third corpus text -->
  </text>
 </TEI>
</teiCorpus>

15.3.2 Declarable Elements

Certain of the elements which can appear within a TEI Header are known as declarable elements. These elements have in common the fact that they may be linked explicitly with a particular part of a text or corpus by means of a decls attribute on that element. This linkage is used to over-ride the default association between declarations in the header and a corpus or corpus text. The only header elements which may be associated in this way are those which would not otherwise be meaningfully repeatable.

Declarable elements are all members of the class att.declarable; the corresponding declaring elements are all members of the the class att.declaring.
  • att.declarable 提供屬性，用於TEI標頭內可單獨以特殊目的的屬性decls選出的元素。
    default當父元素被選擇時，指出此元素是否會被選擇。
  • att.declaring 提供元素屬性，這些元素可單獨與標頭中一特定可宣告元素相關連，因此超越該特定元素本身的預設值。
    decls指明標頭內一個或多個可宣告元素，可應用於帶有此屬性與內容的元素上。
An alphabetically ordered list of declarable elements follows:
  • availability 提供關於文件可利用性的資訊，例如使用或發行上的任何限制、版權狀態等。
  • bibl (書目資料) 包含結構零散的書目資料，其中次要元件不一定會明確標記。
  • biblFull 包含結構完整的書目資料，其中呈現出TEI檔案描述內的所有元件。
  • biblStruct (結構次要書目) 包含僅出現子節點的結構書目資料，並以特定順序呈現。
  • broadcast 描述口說文本的公開播送影音來源相關資訊。
  • correction (更正原則) 說明文本中的更正是在什麼情況下、如何產生的。
  • editorialDecl (編輯實行宣告) 提供文件編碼時使用的編輯原則與實行方法的細節。
  • equipment 提供錄製設備及媒介的技術性細節，該設備及媒介用於口說文本來源之影像或聲音錄製。
  • hyphenation 概述來源文件裡的連字符號在電子化的版本中是如何被處理的。
  • interpretation 指出除了轉錄之外，文件中加入哪些分析性或詮釋性的資訊。
  • langUsage (語言使用) 描述文件中使用的語言、次要語言、語域、方言等。
  • listBibl (書目列表) 包含任何種類的書目資料列表。
  • normalization 指出來源文件轉換成電子文本時規格化或標準化的程度。
  • particDesc (參與描述) 描述在一個語言互動中可辨識的說話者、聲音或其他參與者。
  • projectDesc (計畫描述) 詳述將電子檔案編碼的目標或目的，以及其他關於檔案匯集或收集程序的任何資訊。
  • quotation 說明在編輯上是如何處理來源文件中的引文符號。
  • recording (影音錄製) 包含口說文本的影像或聲音來源錄製細節，該來源可以是直接錄製或是經由公開播放的管道取得。
  • samplingDecl (取樣宣告) 以篇章描述的方式說明建立文集或文選時文件取樣的原理與方法。
  • scriptStmt (腳本陳述) 包含口說文本的來源腳本相關細節。
  • segmentation 描述文件分割的原理方法，例如分割成句子、音調單位、字形層次等。
  • sourceDesc 提供所製電子文件的一個或數個來源文件的書目描述。
  • stdVals (標準值) 明確說明文本中標準化日期或數值所使用的格式。
  • textClass (文件分類) 匯集以標準分類架構、索引典等來描述文件性質或主題的資訊。
  • textDesc (文本描述) 提供文本在情境特徵方面的相關描述。
All of the above elements may be multiply defined within a single header, that is, there may be more than one instance of any declarable element type at a given level. When this occurs, the following rules apply:
  • every declarable element must bear a unique identifier
  • for each different type of declarable element which occurs more than once within the same parent element, exactly one element must be specified as the default, by means of the default attribute
In the following example, an editorial declaration contains two possible correction policies, one identified as CorPol1 and the other as CorPol2. Since there are two, one of them (in this case CorPol1) must be specified as the default:
<editorialDecl>
 <correction xml:id="CorPol1" default="true">
  <p> ... </p>
 </correction>
 <correction xml:id="CorPol2">
  <p> ... </p>
 </correction>
 <normalization xml:id="n1">
  <p> ... </p>
  <p> ... </p>
 </normalization>
</editorialDecl>
For texts associated with the header in which this declaration appears, correction method CorPol1 will be assumed, unless they explicitly state otherwise. Here is the structure for a text which does state otherwise:
<text>
 <body>
  <div1 n="d1"/>
  <div1 n="d2" decls="#CorPol2"/>
  <div1 n="d3"/>
 </body>
</text>
In this case, the contents of the divisions D1 and D3 will both use correction policy CorPol1, and those of division D2 will use correction policy CorPol2.

The decls attribute is defined for any element which is a member of the class declaring. This includes the major structural elements text, group, and div, as well as smaller structural units, down to the level of paragraphs in prose, individual utterances in spoken texts, and entries in dictionaries. However, TEI recommended practice is to limit the number of multiple declarable elements used by a document as far as possible, for simplicity and ease of processing.

The identifier or identifiers specified by the decls attribute are subject to two further restrictions:
  • An identifier specifying an element which contains multiple instances of one or more other elements should be interpreted as if it explicitly identified the elements identified as the default in each such set of repeated elements
  • Each element specified, explicitly or implicitly, by the list of identifiers must be of a different kind.
To demonstrate how these rules operate, we now expand our earlier example slightly:
<encodingDesc>
 <editorialDecl xml:id="ED1" default="true">
  <correction xml:id="C1A" default="true">
   <p> ... </p>
  </correction>
  <correction xml:id="C1B">
   <p> ... </p>
  </correction>
  <normalization xml:id="N1">
   <p> ... </p>
   <p> ... </p>
  </normalization>
 </editorialDecl>
 <editorialDecl xml:id="ED2">
  <correction xml:id="C2A" default="true">
   <p> ... </p>
  </correction>
  <correction xml:id="C2B">
   <p> ... </p>
  </correction>
  <normalization xml:id="N2A">
   <p> ... </p>
  </normalization>
  <normalization xml:id="N2B" default="true">
   <p> ... </p>
  </normalization>
 </editorialDecl>
</encodingDesc>

This encoding description now has two editorial declarations, identified as ED1 (the default) and ED2. For texts not specifying otherwise, ED1 will apply. If ED1 applies, correction method C1A and normalization method N1 apply, since these are the specified defaults within ED1. In the same way, for a text specifying decls as ‘ED2’, correction C2A, and normalization N2B will apply.

A finer grained approach is also possible. A text might specify <text decls='C2B N2A'>, to ‘mix and match’ declarations as required. A tag such as <text decls='ED1 ED2'> would (obviously) be illegal, since it includes two elements of the same type; a tag such as <text decls='ED2 C1A'> is also illegal, since in this context ED2 is synonymous with the defaults for that editorial declaration, namely C2A N2B, resulting in a list that identifies two correction elements (C1A and C2A).

15.3.3 Summary

The rules determing which of the declarable elements are applicable at any point may be summarized as follows:
  1. If there is a single occurrence of a given declarable element in a corpus header, then it applies by default to all elements within the corpus.
  2. If there is a single occurrence of a given declarable element in the text header, then it applies by default to all elements of that text irrespective of the contents of the corpus header.
  3. Where there are multiple occurrences of declarable elements within either corpus or text header,
    • each must have a unique value specified as the value of its xml:id attribute;
    • one only must bear a default attribute with the value YES.
  4. It is a semantic error for an element to be associated with more than one occurrence of any declarable element.
  5. Selecting an element which contains multiple occurrences of a given declarable element is semantically equivalent to selecting only those contained elements which are specified as defaults.
  6. An association made by one element applies by default to all of its descendants.

15.4 Linguistic Annotation of Corpora

Language corpora often include analytic encodings or annotations, designed to support a variety of different views of language. The present Guidelines do not advocate any particular approach to linguistic annotation (or ‘tagging’); instead a number of general analytic facilities are provided which support the representation of most forms of annotation in a standard and self-documenting manner. Analytic annotation is of importance in many fields, not only in corpus linguistics, and is therefore discussed in general terms elsewhere in the Guidelines.47 The present section presents informally some particular applications of these general mechanisms to the specific practice of corpus linguistics.

15.4.1 Levels of Analysis

By linguistic annotation we mean here any annotation determined by an analysis of linguistic features of the text, excluding as borderline cases both the formal structural properties of the text (e.g. its division into chapters or paragraphs) and descriptive information about its context (the circumstances of its production, its genre, or medium). The structural properties of any TEI-conformant text should be represented using the structural elements discussed elsewhere in these Guidelines, for example in chapters 3 Elements Available in All TEI Documents and 4 Default Text Structure. The contextual properties of a TEI text are fully documented in the TEI Header, which is discussed in chapter 2 The TEI Header, and in section 15.2 Contextual Information of the present chapter.

Other forms of linguistic annotation may be applied at a number of levels in a text. A code (such as a word-class or part-of-speech code) may be associated with each word or token, or with groups of such tokens, which may be continuous, discontinuous, or nested. A code may also be associated with relationships (such as cohesion) perceived as existing between distinct parts of a text. The codes themselves may stand for discrete non-decomposable categories, or they may represent highly articulated bundles of textual features. Their function may be to place the annotated part of the text somewhere within a narrowly linguistic or discoursal domain of analysis, or within a more general semantic field, or any combination drawn from these and other domains.

The manner by which such annotations are generated and attached to the text may be entirely automatic, entirely manual, or a mixture. The ease and accuracy with which analysis may be automated may vary with the level at which the annotation is attached. The method employed should be documented in the interpretation element within the encoding description of the TEI Header, as described in section 2.3.3 The Editorial Practices Declaration. Where different parts of a corpus have used different annotation methods, the decls attribute may be used to indicate the fact, as further discussed in section 15.3 Associating Contextual Information with a Text.

An extended example of one form of linguistic analysis commonly practised in corpus linguistics is given in section 17.4 Linguistic Annotation.

15.5 Recommendations for the Encoding of Large Corpora

These Guidelines include proposals for the identification and encoding of a far greater variety of textual features and characteristics than is likely to be either feasible or desirable in any one language corpus, however large and ambitious. The reasoning behind this catholic approach is further discussed in chapter iv. About These Guidelines. For most large-scale corpus projects, it will therefore be necessary to determine a subset of TEI recommended elements appropriate to the anticipated needs of the project, as further discussed in chapter 23.2 Personalization and Customization; these mechanisms include the ability to exclude selected element types, add new element types, and change the names of existing elements. A discussion of the implications of such changes for TEI conformance is provided in chapter 23.3 Conformance.

Because of the high cost of identifying and encoding many textual features, and the difficulty in ensuring consistent practice across very large corpora, encoders may find it convenient to divide the set of elements to be encoded into the following four categories:
required
texts included within the corpus will always encode textual features in this category, should they exist in the text
recommended
textual features in this category will be encoded wherever economically and practically feasible; where present but not encoded, a note in the header should be made.
optional
textual features in this category may or may not be encoded; no conclusion about the absence of such features can be inferred from the absence of the corresponding element in a given text.
proscribed
textual features in this category are deliberately not encoded; they may be transcribed as unmarked up text, or represented as gap elements, or silently omitted, as appropriate.

15.6 Module for Language Corpora

The module described in this chapter makes available the following components:
組件 corpus: 文集文本
The selection and combination of modules to form a TEI schema is described in 1.2 Defining a TEI Schema.

↑ 內容 « 14 Tables, Formulæ, and Graphics » 16 Linking, Segmentation, and Alignment

註解
45.
Schemes similar to that proposed here were developed in the 1960s and 1970s by researchers such as Hymes, Halliday, and Crystal and Davy, but have rarely been implemented; one notable exception being the pioneering work on the Helsinki Diachronic Corpus of English, on which see Kytö and Rissanen (1988)
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46.
It is particularly useful to define participants in a dramatic text in this way, since it enables the who attribute to be used to link sp elements to definitions for their speakers; see further section 7.2.2 Speeches and Speakers.
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