2 Syllables: SU
bristling, christening, crippling, differing, giggling, glistening, listening, middling, nibbling, rippling, scribbling, sickening, stiffening, thickening
3 Syllables: SUU
bickering, blistering, dissident, flickering, glimmering, glittering, glycerine, limiting, Pickering, quickening, quivering, rivalling, shimmering, shivering, signaling, signalling, simmering, synonym, tickling, whispering, withering, wriggling
4 Syllables: USUU
conditioning, considering, delivering, eliciting, imprisoning, inhibiting, petitioning, positioning, prohibiting, soliciting
Found 46 words across 3 groupings. Skipped 2 excess words of a similar stem.