2 Syllables: SU
agile, axial, baffle, bashful, Basil, Basle, Cassel, castle, cavil, dazzle, facile, fragile, gravel, nationals, natural, Paschal, rascal, rational, scaffold, tassel, travel, travelled, travels, vassal, wrathful
3 Syllables: SUU
affable, animal, arable, cannibal, capitals, casual, comparable, fallible, lateral, laughable, mackerel, marital, Nationale, passable, pastoral
3 Syllables: USU
4 Syllables: USUU
bilateral, collateral, compatible, diagonal, grammatical, hexagonal, impassable, implacable, infallible, inflammable, irrational, octagonal, pyramidal, unnatural
5 Syllables: UUSUU
Found 60 words across 5 groupings. Skipped 11 excess words of a similar stem.