Focus on the pronunciation of overhear
English definition of “overhear”
/ˌoʊ·vərˈhɪər/ v [I/T] (past tense and past participle overheard /ˌoʊ·vərˈhɜrd/)
› to hear what other people are saying unintentionally and without their knowledge: [T] I overheard a funny conversation on the bus this morning. [I] They were so loud, I couldn’t help overhearing.