If you thought that there can be no such thing since all of humanity belongs to Allah and also their languages then you might pause and think about the following which is taken from a khutbah delivered by Shaykh Saalih bin Fawzaan al-Fawzaan.
Another example of imitating the disbelievers is speaking in their languages unnecessarily;
…..
being accustomed to speak in any language other than Arabic is Makrooh
Now just to be fair, here is the complete paragraph from which the quote is taken from.
Another example of imitating the disbelievers is speaking in their languages unnecessarily; this happens even among the native Arabs in their own countries. The reason why this is so disliked is that when a person speaks a foreign language, he becomes accustomed to this practice and deserts the Arabic tongue which is the symbol of Islaam. In fact, the language spoken is among the greatest of the symbols that define the culture and practices of any given group of people. Therefore, the majority of Islamic jurists are of the view that offering Du’aa’, or supplication, within Salaah, or prayers; and saying Dhikr, or the mentioning of Allaah’s names, in a language other than Arabic is Makrooh, or not recommended.Allaah has glorified the Arabic language, revealed His Book in it and made it the native language of Muhammad (sall-Allaahu ‘alayhi wa sallam), the last of His Prophets. So, being accustomed to speak in any language other than Arabic is Makrooh – if a person knows Arabic – for it leads to resembling non-Muslims, deserting the Arabic language, and replacing it by another language.
Notice how legitimate and not so legitimate arguments are intertwined so that a person not looking carefully enough might miss the illogic behind these arguments. Notice that the conclusion of non-Arabic languages being Makrooh does not follow from the premises. Even the idea of speaking a non-Arabic lanuage leading one to being similar to non-believers borders on imperialism since this would imply that there is only one nationality in Islam, namely being an Arab. Now in the West, Muslims from almost all backgrounds are surprised that many non-Muslims tend to think that most or even all Muslims are Arabs. In the light of such fatwas this not be surprising at all.
