柯林斯詞典mother tongue (mother tongues) 1. N-COUNT Your mother tongue is the language that you learn when you are a baby. 母語(yǔ)[oft poss N] 返回 mother tongue劍橋詞典the first language that you learn when you are a baby , rather than a language learned at school or as an adult 母語(yǔ)；本國(guó)語(yǔ)；本族語(yǔ) 返回 mother tongue