2 Syllables: SU
3 Syllables: SUU
bearable, cerebral, chemical, clerical, credible, decimal, edible, equable, ethical, festival, flexible, genital, legible, medical, metrical, parable, pedestal, plentiful, preferable, Reginald, sceptical, seminal, several, skeletal, skeptical, spectacle, spherical, technical, tenable, terrible, vesicles
4 Syllables: USUU
acceptable, accessible, amenable, chimerical, confessional, congenital, Congressional, delectable, detectable, detestable, electrical, ephemeral, execrable, heretical, hysterical, illegible, impeccable, impregnable, incredible, indelible, ineffable, inflexible, intestinal, numerical, perceptible, poetical, polemical, professional, receptacle, regrettable, respectable, susceptible, symmetrical, unbearable, untenable
5 Syllables: UUSUU
academical, alphabetical, antithetical, arithmetical, asymmetrical, biochemical, dialectical, ecumenical, evangelical, geometrical, imperceptible, inaccessible, incontestable, indigestible, inexpressible, irrepressible, theoretical, unacceptable, unforgettable
6 Syllables: UUUSUU
Found 89 words across 5 groupings. Skipped 9 excess words of a similar stem.