1 Syllable: S
Ian, leant
2 Syllables: SU
beaches, beacon, beaten, chieftain, clearance, cleavage, Cleveland, credence, deacon, decent, deepen, demon, deviant, Eastman, Easton, eaten, Eaton, Eden, Ephraim, eras, Eton, ference, Freedman, freedmen, freedom, Freeman, Freeman's, frequent, Friedman, Grecian, Greenland, grievance, heathen, helium, leakage, legion, Leland, lenient, lesion, median, medium, Museum, peaches, peerage, Pekin, pieces, piquant, premium, prescience, reaches, reagent, reason, recent, refund, Regent, region, seaman, seamen, season, semen, sequence, serum, speaketh, speeches, Stephen, Steven, Sweden, sweeten, teaches, tedium, theorem, treason, treatment, weaken, Zealand
2 Syllables: US
3 Syllables: SUU
3 Syllables: USU
accretion, achievement, adherence, adherent, adhesion, agreement, allegiance, appearance, Archdeacon, arenas, Armenian, Athenian, bereavement, Bohemian, caprices, Cartesian, chameleon, coherence, coherent, cohesion, comedian, completion, concealment, convenience, convenient, depletion, diseases, Ephesians, excretion, expedient, impeachment, indecent, infrequent, ingredient, magnesium, Norwegian, obedience, obedient, Phoenician, policeman, reappearance, secretion, uneven, unfrequent, Venetian
3 Syllables: UUS
4 Syllables: UUSU
antecedent, disagreement, disappearance, disobedience, disobedient, epithelium, incoherence, incoherent, inconvenience, inconvenient, inexpedient, interference, paroxysms, perseverance
4 Syllables: UUUS
5 Syllables: UUUSU
Found 152 words across 9 groupings. Skipped 45 excess words of a similar stem.