60 lines
3.1 KiB
XML
60 lines
3.1 KiB
XML
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<page title="Tag wisely">
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<p>(Most of the content on this page comes directly from
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<wikipedia name="Request for Comments">RFC</wikipedia> 5646.)</p>
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<p>For the same body of text, you may have several possible
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tags. Interoperability is best served when all users use the same
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language tag for the same language. The rules here are intended to
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help in that respect.</p>
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<p>Subtags should only be used where they add useful distinguishing
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information; extraneous subtags interfere with the meaning,
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understanding, and processing of language tags. In particular, fields
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<code>Suppress-Script</code> in the registry should be obeyed: for
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instance, <code>fr</code> (<wikipedia name="French language">French</wikipedia>) has a
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<code>Suppress-Script: Latn</code> because the overwhelming majority
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of French texts are in the <wikipedia>Latin script</wikipedia>. Therefore, tagging text in French as
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<code>fr-Latn</code> is useless and confusing. A simple
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<code>fr</code> is enough. In the unlikely case that you meet French
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texts in the <wikipedia>Arabic script</wikipedia>, then you can add a subtag for the script:
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<code>fr-Arab</code>. (This is specially important since the former
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standard, in RFC 3066, did not have subtags for scripts and therefore
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old applications will have problems to handle them.)</p>
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<p>Use as precise a tag as possible, but no more specific than is
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justified. Avoid using subtags that are not important for
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distinguishing content in an application. For example, <code>de</code>
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might suffice for tagging an email written in
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<wikipedia name="German language">German</wikipedia>, while <code>de-CH-1996</code>, while
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legal,is probably unnecessarily precise for such a task.</p>
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<p>But do not be too vague: the primary language subtag might not be
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sufficient to give all the information necessary to understand the
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text. For
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example, the tag <code>az</code> (for
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<wikipedia name="Azerbaijani language">Azerbaidjani</wikipedia>) is probably insufficient in the
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absence of context, because this language has no dominant script. A person fluent in
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one script might not be able to read the other, even though the text
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might be identical. Content tagged as <code>az</code> most probably is written
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in just one script and thus might not be intelligible to a reader
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familiar with the other script. <code>az-Latn</code>,
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<code>az-Cyrl</code> or <code>az-Arab</code> are probably necessary.</p>
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<p>If a tag or subtag has a <code>Preferred-Value</code> field in its registry
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entry, then the value of that field should be used to form the
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language tag. For example, use <code>he</code> for <wikipedia
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name="Hebrew language">Hebrew</wikipedia> in preference to
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<code>iw</code>.</p>
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<p>Validity of a tag is not everything. A tag may be both valid and
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meaningless. This is unavoidable with a generative system like the
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language subtag mechanism. So, <code>ar-Cyrl-AQ</code>
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(<wikipedia>Arabic</wikipedia> written with the <wikipedia name="Cyrillic alphabet">cyrillic
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script</wikipedia>, as used in <wikipedia>Antarctica</wikipedia>) is
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perfectly valid but should nevertheless be avoided because it has no
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relationship with the reality (there is not a single document with
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these characteristics).</p>
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</page>
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