He played a traditional folk song on his dulcimer during music class.

dulcimer 是一种弦乐器，源自拉丁语 dulcis（甜美的）和 melos（歌曲）的组合，字面意思是"甜美的歌曲"。这种乐器通常有金属弦，用琴槌敲击演奏，在中文里称为"扬琴"。