...
It's short, clear and has examples – read it please – but here are some emphasis points:
Mostly you should think of the "Language of Text" as a proxy for the language used by the audience.
- The "Language of Text" code is used to tell a retailer of books in that language that this is a product they can sell to their customers – it's the simple case above. If the book does include multiple languages then the MAY be reasons to list them all, but when in doubt make it easy for the retailer. There really aren't many genuinely multilingual titles which I'm defining as a book that can be SOLD by retailers to readers in the different languages. One way to tell that you have one is if you can create a full bibliographical record in all the languages listed as Language of Text. For example: If the book title is only in one of the languages do you seriously think a retailer can sell it in another language?
- An excellent explanation of when to use multiple Language of Text codes is covered in EDItEUR's guide
Language instruction books should be sold to the language who will use the book.
- I know! Duh. But it's the same point again: The fact the might contain text in two languages doesn't change anything and it's still a proxy for the language used by the audience – only one of them is the "Language of the Text."
- The language being learned is a Subject of the book and should be fully listed in that section of the metadata. THEMA has an excellent system for handling most any language of instruction. Again, just think of the retailer selling the book – you want retailers selling in the audience's language to stock and list the title – in the right section: Language Instruction filed by that Subject language.
- A special case is allowed for – and it really is a special case so don't expect to use it unless the book matches this
What if the book is in Russian – the language of the whole text is <LanguageCode>rus</LanguageCode> – but it's a book in Russian designed specifically to be used by English language speakers – so, it's like a book in Russian but it's for English speakers. HA! Solve that Mr. ONIX! You can't fudge the language of the text there.
- There's a limit to how much Language of Text can be a proxy for audience but this isn't just whimsy and a real use case so Mother ONIX provides for it by using the Audience Composite: ONIX Code List 29, code "27" is for the Language of the Intended Audience. It allows you to name the audience language for a book in a different one. The book should be in one language and specifically designed for readers in another – otherwise don't use this.
- To be clear: In day-to-day life retailers will look to the Language Composite for the Language of text to know what audience they should sell to. In this very specialized case a data sender can highlight the special audience consideration of this foreign language text to retailers in another language. But if you fit the normal, simple, use case and "back-up" your Language of Text value by duplicating it as the Language of the Intended Audience all you do is cloud the data. You force retailers to clean their data by looking for matches between the values and removing your unnecessary one. They won't thank you for that so don't do it – good granular metadata means letting the special case metadata to do its work and not adding values because it looks like you can.
Information about Translations
- The Language Composite offers other Language Role codes for other purposes, including "02" for the Original language of a translated text, with the explanatory note "Where the text in the original language is NOT part of the current product." So you can supply the original language for a translation easily.
- One use of more than one "Language of Text" codes would be for a book where a translation was on facing pages with the original language. There both Languages should be listed as Code "01". Does this contradict the "retailer" advice above? Yes - so use discretion here (when in doubt make it easy for the retailer selling the book) – but facing translations have value in both languages and it's hard to cover everything in the metadata perfectly. I would recommend making sure the primary audience language (the language of Introduction and comments, etc.) is listed first. Order is paid attention to by many retailers.
- There is another place to list information on translations: The Contributor Composite where you give the Translator's information block can list the language that the translator worked from.
...
Supplementary assignment: Give examples of ways a publisher can defeat any metadata standard. Bonus points for commissioning a book that does it.
Summary
Don't rely on this page for all you need to know. You should go read the P.10 Language section in ONIX for Books Implementation and Best Practice Guide. It's short, practical and comprehensive, providing language knowledge without the sophomoronic humour.
...