参加音乐比赛的英语是 "participate in a music competition"。这个短语来源于英语动词 "participate" 和名词 "music competition" 的结合。"Participate" 意思是参与，而 "music competition" 指音乐比赛。
例句：
I'm excited to participate in the music competition this weekend. 我很高兴能参加这个周末的音乐比赛。
My daughter has been practicing for months to participate in the music competition. 我的女儿已经练习了几个月，准备参加音乐比赛。
Many talented musicians will participate in the music competition this year. 今年将有很多才华横溢的音乐家参加音乐比赛。