2 Syllables: SU
blurring, burning, bursting, chirping, churning, circling, curbing, curling, cursing, curving, during, earning, Erwin, flirting, gurgling, herding, herdsmen, hurling, hurting, Irving, Irwin, jerking, learning, lurking, merging, Merlin, nursing, Perkins, purging, searching, serving, skirting, spurring, sterling, Stirling, stirring, sturgeon, surgeon, surging, swirling, thirsting, turning, twirling, urging, verging, vermin, virgin, whirling, whirlwind, working, workmen, worsening, yearning
3 Syllables: SUU
3 Syllables: USU
adverting, affirming, asserting, averting, concerning, concurring, conferring, confirming, conserving, converging, conversing, converting, deferring, deserving, discerning, dispersing, disturbing, diverging, diverting, encircling, exerting, immersing, incurring, inferring, inserting, inverting, manoeuvring, observing, occurring, perverting, preferring, preserving, recurring, referring, rehearsing, reserving, returning, reversing, reverting, transferring, traversing, unswerving, usurping
4 Syllables: UUSU
Found 101 words across 4 groupings. Skipped 6 excess words of a similar stem.