The origin of yodeling is interesting. One evening while trudging his weary way between Swiss villages, a travelling ski wax
salesman got caught in a blizzard.

That accounts only for Swiss yodeling. Here in the Yew Ess Aye, yodeling got its start from a lack of wax salesmen. Just watch on old Western movie, the ones with the singing cowboys, and you'll notice that they yodeled because they hadn't waxed the splintery seat planks on the wagons.