Or search: roar, yell, yowl, hollo, shout, holla, bellow, holler, holloa, roaring, bellowing, vociferation
2 Syllables: SU
broadening, jostling, modeling, offering, quarreling, softening
3 Syllables: SUU
aldermen, altering, auditing, blossoming, bothering, faltering, fostering, gossiping, honoring, honouring, modelling, profiting, promising, prospering, slaughtering, tottering, vomiting, watering

Found 24 words across 2 groupings. Skipped 1 excess word of a similar stem.