Currently, the following languages are supported by the engine(the names in braces are the identifiers you would need to use in Zettlr, as they do not contain special characters, which might upset an engine).
Besides the former colonial languages of English, French, Portuguese and Spanish, the following languages are official at the national level in Africa.
English
中文
عربى
Български
বাংলা
Český
Dansk
Deutsch
Ελληνικά
Español
Suomi
Français
עִברִית
हिंदी
Hrvatski
Magyar
Bahasa indonesia
Italiano
Қазақ
한국어
മലയാളം
मराठी
Bahasa malay
Nederlands
Norsk
Polski
Português
Română
Русский
Slovenský
Slovenski
Српски
Svenska
தமிழ்
తెలుగు
ไทย
Tagalog
Turkce
Українська
اردو
Tiếng việt