What is the word „mother tongue“ in your language? Is it related to the word „mother“?
In GERMAN:
die Muttersprache (the language of the mother)
Portuguese: Língua materna and Spanish: lengua materna
Here is an interesting write up on mother tongue:
Stop wondering :) It is apt that the language a child speaks is attributed to mother as mother gives birth and takes care of baby and the child usually stays with mother and hence learns the language spoken by mother. There might be few exceptions in some languages but if you dig a little deeper or scratch the surface a bit, you may find it related to mother indirectly.
One more reason :Language we speak at home is called mother tongue not father tongue because father is not allowed to speak at home. ;-)
I still wonder if there is any language where the word "mother tongue" is not related to the word "mother"
In french, it is "langue maternelle", the mother's language !