The following languages are already available to communities in the WordPress admin:
- English (US) 100%
- English (UK) 100%
- Portuguese (Brazil) 100%
- Swedish 100%
The following languages can be installed upon request (ask in Mozilla Communities Web Services top category):
- Afrikaans 100%
- German 100%
- Slovenian 100%
- English (Australia) 100%
- English (Canada) 100%
- English (New Zealand) 100%
- Serbian 100%
- Russian 100%
- French (France) 100%
- French (Belgium) 100%
- French (Canada) 100%
- Romanian 100%
- Portuguese (Portugal) → Portuguese (Portugal) AO90 100%
- Portuguese (Portugal) 100%
- Galician 100%
- German → German (Formal) 100%
- Dutch (Belgium) 100%
- Greek 100%
- Polish 100%
- Gujarati 100%
- Norwegian (Nynorsk) 100%
- Hebrew 100%
- Hindi 100%
- Indonesian 100%
- Italian 100%
- Japanese 100%
- Javanese 100%
- Kabyle 100%
- Malay 100%
- Korean 100%
- Albanian 100%
- Dutch → Dutch (Formal) 100%
- Esperanto 100%
- Dutch 100%
- Catalan 100%
- Welsh 100%
- Urdu 100%
- Turkish 100%
- Thai 100%
- Basque 100%
- Spanish (Spain) 100%
- Bulgarian 100%
- Spanish (Guatemala) 100%
- Belarusian 100%
- Lithuanian 100%
- Czech 100%
- Spanish (Argentina) 100%
- Chinese (Hong Kong) 100%
- Croatian 100%
- Chinese (China) 100%
- Arabic 99%
- Malayalam 99%
- Marathi 99%
- Finnish 99%
- Spanish (Venezuela) 99%
- Uzbek 99%
- Vietnamese 99%
- Ukrainian 99%
- Slovak 99%
- Nepali 99%
- Danish 99%
- Spanish (Chile) 99%
- Occitan 99%
- German (Switzerland) 99%
- Spanish (Colombia) 99%
- Spanish (Costa Rica) 99%
- Estonian 99%
- Spanish (Mexico) 99%
- Georgian 99%
- Bengali 99%
- German (Switzerland) → German (Switzerland) Informal 99%
- Chinese (Taiwan) 99%
- Norwegian (Bokmål) 99%
- Persian 99%
- Latvian 98%
- Icelandic 98%
- Hungarian 97%
- English (South Africa) 95%
- Macedonian 94%
- Moroccan Arabic 93%
- Tagalog 93%
- Khmer 93%
- Tamil
- Kazakh
- Tatar
- Kurdish (Sorani)
- Telugu
- Punjabi
- Uighur
- Azerbaijani
- Tibetan
- Armenian
- Sakha
- Spanish (Peru)
- Scottish Gaelic
- Silesian
- Bosnian
- Lao
- Sinhala
- Mongolian
- South Azerbaijani
- Dzongkha
- Rohingya
- Tahitian
- Cebuano
- Hazaragi
- Swahili
- Amharic
- Tamil (Sri Lanka)
- Assamese
- Pashto
- Myanmar (Burmese)
- Asturian
- Kannada
- Breton
- Irish
- Romansh
- Portuguese (Portugal) → Portuguese (Portugal) Informal
- Luxembourgish
- Faroese
- Montenegrin
- Somali
- Persian (Afghanistan)
- Sindhi
- Aragonese
- Frisian
- Sundanese
- Ossetic
- Kyrgyz
- Malagasy
- Algerian Arabic
- Oriya
- Hausa
- Tajik
- Corsican
- Tamazight (Central Atlas)
- Arpitan
- Dhivehi
- Sanskrit
- Shona
- Emoji
- Turkmen
- Balochi Southern
- Fulah
- Shqip (Kosovo)
Check the updated list on Wordpress Translation project.