What is the correct way to use the lang attribute with phonetic pronunciations (if at all)?
html, localization
Solution
Short version: if you want to specifically say it's written in the Latin alphabet, go for "hi-Latn" or "ga-Latn" for the examples you gave.
Long version:
The W3C spec for the lang attribute doesn't specifically mention this - it suggests some uses of this that depend on orthography (such as using it in order to render high-quality versions of the characters used), but some that don't (such as for search engines).
RFC1766, which specifies the format for the language tags, suggests that specialisations of tags may be used to represent "script variations, such as az-arabic and az-cyrillic". There's more about the script subtag in this article on the W3C site, and a bit extra in the later RFC5646. That one points to an ISO standard list of script names, and in that list the script you'd want is "Latn" as they're romanised forms of other scripts.
(This doesn't cover things like specifying how you did the transliteration, though, for languages which may have more than one standard e.g. Chinese in Latin script using Wade-Giles versus pinyin.)
Problem
Some languages have an accepted transliteration to Latin characters, such as Hindi, Russian or Japanese. For example, the Hindi for 'The man is eating' written in Devanagari script is 'आदमी खा रहा है।'. Transliterated, it would be 'Aadmi kha raha hai.' (or something similar; this approach is often used online, especially if people don't have access to a Hindi keyboard.) In this case, we're using the Latin script but still writing Hindi, so it would be acceptable to mark up either variation using the `lang` attribute: `<span lang="hi">आदमी खा रहा है।</span>` or `<span lang="hi">Aadmi kha raha hai.</span>` My question then is about languages that are normally written in the Latin alphabet themselves, but might have phonetic guides for non-speakers/learners — either IPA or ad hoc pronunciation — is there any best practice in terms of giving it semantic meaning? For example, in Irish if I were to say "The man is eating", I would say "Tá an fear ag ithe." I can mark this up as: `<span lang="ga">Tá an fear ag ithe.</span>` If I were to give a pronunciation guide for non-speakers, I might say "Taw on far eg ih-he". The sentence isn't meaningless, (like 'lorem ipsum' text) but neither is the sentence in either English or Irish. What is the correct use of language related attributes in HTML in this case, or is this use case just not covered currently by the specification?