The hummel is a folk instrument of Swedish/German origin. It is known by its distinctive teardrop shape. Like its cousin, the dulcimer, the hummel is a modal instrument. But while dulcimers commonly have four strings, hummels have five or more.
Mine is a five string with an unfretted bass string that remains in open drone. I play melody on the other bass string and the middle string, leaving double treble strings in open drone as well.
My hummel was made in California by Bryan Mumford in 1973. Joni Mitchell has one from the same series.