Ok, if it is not published, we can try to at least figure this out.
Let me put this table for the beginning and we will refine it if someone has more information.
I’m making assumption that supported languages shall be similar to those supported by voice search and that google uses standard language codes and does that consistently across its services.
I’ve looked up languages supported by voice search on wikipedia
I’ve found language codes here, on google language settings page and here
EDIT:
I’ve experimented with backend voice recognition service. I’ve run a series of tests where I’ve passed the same english speech sample to the API but specified different dialect every time. It looks like:
- If a language is not supported, recognition falls back to en-US (looks like it recognizes that the sample is in english)
- If a dialect is not supported (or doesn’t exist) recognition falls back to main dialect or en-US in some cases
- Main dialect can be specified just as first part of identifier. So ‘en-US’ and ‘en’ gives same results.
- Recognition for some languages, like chinese and japanese gives results in english, different from en-US though, which is strange. Probably the sample is different very much from chinese and the service is clever to figure that out.
I treat a dialect as supported if recognition gives a different result from en-US and from main dialect for the language. Still, to verify it 100% we need to run samples for each language.
Legend
+Most of all supported, because test gives a result different from en-US and main dialect..+Absent on wikipedia but most of all supported, because test gives result different from en-US and main dialect.+?Most of all supported because it is listed on wikipedia. But test on my sample gives result identical to the main dialect. So either this is a coinsidense or language code is wrong..+?Not listed on wikipedia but looks like supported, because test gives result different from en-US and main dialect.
Languages
+Afrikaans af+Basque eu+Bulgarian bg+Catalan ca+Arabic (Egypt) ar-EG+?Arabic (Jordan) ar-JO+Arabic (Kuwait) ar-KW+?Arabic (Lebanon) ar-LB+Arabic (Qatar) ar-QA+Arabic (UAE) ar-AE.+Arabic (Morocco) ar-MA.+Arabic (Iraq) ar-IQ.+Arabic (Algeria) ar-DZ.+Arabic (Bahrain) ar-BH.+Arabic (Lybia) ar-LY.+Arabic (Oman) ar-OM.+Arabic (Saudi Arabia) ar-SA.+Arabic (Tunisia) ar-TN.+Arabic (Yemen) ar-YE+Czech cs+Dutch nl-NL+English (Australia) en-AU+?English (Canada) en-CA+English (India) en-IN+English (New Zealand) en-NZ+English (South Africa) en-ZA+English(UK) en-GB+English(US) en-US+Finnish fi+French fr-FR+Galician gl+German de-DE+Hebrew he+Hungarian hu+Icelandic is+Italian it-IT+Indonesian id+Japanese ja+Korean ko+Latin la+Mandarin Chinese zh-CN+Traditional Taiwan zh-TW+?Simplified China zh-CN ?+Simplified Hong Kong zh-HK+Yue Chinese (Traditional Hong Kong) zh-yue+Malaysian ms-MY+Norwegian no-NO+Polish pl+?Pig Latin xx-piglatin+Portuguese pt-PT.+Portuguese (brasil) pt-BR+Romanian ro-RO+Russian ru+Serbian sr-SP+Slovak sk+Spanish (Argentina) es-AR+Spanish(Bolivia) es-BO+?Spanish( Chile) es-CL+?Spanish (Colombia) es-CO+?Spanish(Costa Rica) es-CR+Spanish(Dominican Republic) es-DO+Spanish(Ecuador) es-EC+Spanish(El Salvador) es-SV+Spanish(Guatemala) es-GT+Spanish(Honduras) es-HN+Spanish(Mexico) es-MX+Spanish(Nicaragua) es-NI+Spanish(Panama) es-PA+Spanish(Paraguay) es-PY+Spanish(Peru) es-PE+Spanish(Puerto Rico) es-PR+Spanish(Spain) es-ES+Spanish(US) es-US+Spanish(Uruguay) es-UY+Spanish(Venezuela) es-VE+Swedish sv-SE+Turkish tr+Zulu zu