Does any other prophets speaks arabic? No. So what i see here, with the word muslim is not an absolute "arabic name", but some kind of qualifier name. So in my opinion, calling yourself "Someone who submit", "believer", "monotheist", "quran alone" or even "quranist" isn't always wrong. Choose whatever best identifier in any language to better relate to others. What matters is if we really worship only God and following His way. The one who clearly wrong is those who making a cult from such name, creating divisions "we're God's chosen people/you should join us/use this name too" which is clearly not God's way.. Verse (2:135) came to mind, because that is precisely what today (traditional) "muslim" do.