1、生日快乐的英文为：happy birthday，读音：英[ˈhæpi ˈbɜːθdeɪ]，美[ˈhæpi ˈbɜːrθdeɪ]。

2、[例句]The cake had Happy Birthday piped on it.蛋糕上裱了“生日快乐”的字样。