2 Syllables: SU
Adam, adjunct, Alan, Allan, Allen, Allen's, alum, Ammon, annum, Arian, ashen, aspen, Aston, Athens, atom, balance, Baron, barren, baton, blacken, bracken, cabin, cannon, canon, Caspian, challenge, chaplain, chasm, Chatham, datum, dragon, famine, fashion, fasten, fathom, fatten, flatten, gallant, gallon, Gaston, gladden, Hallam, Hammond, happen, Hatton, javelin, Kaplan, Latham, Latin, Madam, Madame, Madden, Mammon, Masson, matin, pageant, passion, patent, Patton, phantom, ration, saddened, saffron, salmon, satin, savants, Shannon, Sharon, slacken, spasm, Staten, Stratton, stratum, talent, talons, waggon, wagon
3 Syllables: USU
4 Syllables: UUSU

Found 92 words across 3 groupings. Skipped 44 excess words of a similar stem.