The language the user's operating system is running in. Returned by Application.systemLanguage.
| Afrikaans | Afrikaans. |
| Arabic | Arabic. |
| Basque | Basque. |
| Belarusian | Belarusian. |
| Bulgarian | Bulgarian. |
| Catalan | Catalan. |
| Chinese | Chinese. |
| Czech | Czech. |
| Danish | Danish. |
| Dutch | Dutch. |
| English | English. |
| Estonian | Estonian. |
| Faroese | Faroese. |
| Finnish | Finnish. |
| French | French. |
| German | German. |
| Greek | Greek. |
| Hebrew | Hebrew. |
| Icelandic | Icelandic. |
| Indonesian | Indonesian. |
| Italian | Italian. |
| Japanese | Japanese. |
| Korean | Korean. |
| Latvian | Latvian. |
| Lithuanian | Lithuanian. |
| Norwegian | Norwegian. |
| Polish | Polish. |
| Portuguese | Portuguese. |
| Romanian | Romanian. |
| Russian | Russian. |
| SerboCroatian | Serbo-Croatian. |
| Slovak | Slovak. |
| Slovenian | Slovenian. |
| Spanish | Spanish. |
| Swedish | Swedish. |
| Thai | Thai. |
| Turkish | Turkish. |
| Ukrainian | Ukrainian. |
| Vietnamese | Vietnamese. |
| Unknown | Unknown. |
| Hungarian | Hungarian. |