Wiktionary
sowth
vb. (context Scotland English) to hum or whistle a low tone
Usage examples of "sowth".
And on the iv daie hadd notise of a gret powre and strengtht cumming at me from sowth out of Owleswyke to assaille mee in Grunda.
More beginnith at the west syde of the mowth of Arlan and occupiethe all the lond unto the hedeland Sibrion, and therefro sowth awaye to the Corshe, by gesse a vii hundered myles, wherby the se is not ther of nature favorable nor no haven is or cumming yn meete for shippes.