Within Tarteel, you can choose the language of the app's menus and buttons. This is separate from Quran translations: Tarteel has 152 Quran translations in 76 languages and 45 tafsirs in 20 languages. See Translations.
The app itself is available in these 12 languages:
English
Arabic
French
Bahasa Melayu
Bahasa Indonesia
Russian
Turkish
Spanish
German
Hausa
Urdu
Portuguese
We're constantly working to increase the number of languages we provide on Tarteel. If you don't see your language, please request it here: https://feedback.tarteel.ai/. While we can't guarantee it will be in immediate development, we'll endeavour to get it on the roadmap inshaAllah.