Here is the complete list for languages that support turn-by-turn directions now:
Afrikaans, Arabic (North African), Arabic (Saudi Arabia), Basque, Bulgarian, Cantonese, Catalan, Croatian, Czech, Danish, Dutch, English (UK), English (US) – male & female, Estonian, Farsi, Finnish, French (Canada), French (France), Galician, German, Greek, Hindi, Hungarian, Icelandic, Indonesian, Italian, Korean (South Korea), Latvian, Lithuanian, Malay, Mandarin (China), Mandarin (Taiwan), Norwegian, Polish, Portuguese (Brazil), Portuguese (Portugal), Romanian, Russian, Serbian, Slovak, Slovenian, Spanish (Latin America), Spanish (Mexico), Spanish (Spain), Swahili, Swedish, Tagalog, Tamil, Thai, Turkish, Ukrainian, Urdu and Vietnamese.
Here’s the list of all UI languages supported now,
Czech, Dutch, English (UK), English (US), Finnish, French, German, Hindi, Indonesian (Bahasa), Italian, Malay (Bahasa), Polish, Portuguese (Brazil), Russian, Spanish (Spain), Spanish (Mexico), Thai, Turkish and Vietnamese.