Answered by Ustadha Shazia Ahmad
I heard that in the Shafii madhab it is haram for Muslims who know Arabic to speak in any language other than Arabic when they are amongst each other. Is this correct? And does this apply to someone who may not know much Arabic but is fluent in the colloquial (such as colloquial Egyptian or Jordanian)?
Answer:
It is not haram in the Shafi’I madhhab, nor in any school to speak in a language other than Arabic if one knows Arabic.
As He Most High said in the Quran, Allah has created us in tribes and nations so that we may know one another, not so that we can all be Arabized.
And Allah alone knows best.