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[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；本國(guó)語；本族語 返回 mother tongue