Questioner: Is it obligatory on the student of legislated knowledge to learn the Arabic language and speak it?
Al-Albaani: Learning the Arabic language is an obligatory issue due to what is established with the scholars that: those things which an obligatory action cannot be established without are obligatory themselves. And it is not possible for a student of knowledge to understand the Quraan and the Sunnah except through the Arabic language.
As for speaking it, then that is something recommended [mustahab] due to the lack of a legislated proof obligating it.
Fataawaa ash-Shaikh al-Albaani fil-Madinah wal-Imaaraat, 35.