The Swedish term "knot, brumma, knota" matches the English term "grumble"

other swedish words that include "brumma" : english :
morrande, morra, brumma growl
väft, brumma woof
surra, brumma, zoom zoom
other swedish words that include "knota" : english :
ben, knota bone
knotar grumbles
mummel, sorla, knota, porla, mumla, susa murmur