Crossword Genius

Language of one's country of birth (6,6)

Ross

I believe the answer is:

mother tongue

(Other definitions for mother tongue that I've seen before include "Native language" , "Language used" .)

I've seen this clue in the Sydney Morning Herald.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.