English - mother French - mere Czech - matka Hindi - maan mandarin - 媽媽 (mama) or 母親 (mu qin)
this could be more of a linguistics question though.
Because infants can utter bilabial sounds like [m], [b] and [p] very early and adults have perceived these sound combinations as words for the people the infants are around the most in their first few months. But I’m far from an expert in first language acquisition and you can get more qualified answers in /r/Linguistics