Or search: fetal
1 Syllable: S
Crowell, Joel, Lowell
2 Syllables: SU
boastful, choral, coastal, coral, doleful, floral, focal, global, hopeful, jovial, laurel, local, mobile, modal, Mogul, moral, noble, opal, oral, oval, postal, quarrel, quarrelled, quarrels, social, sorrel, total, vocal, Vogel, woeful
2 Syllables: US
bestowal
3 Syllables: USU
baronial, betrothal, colloquial, colonial, disposal, ennoble, ignoble, immobile, immoral, parochial, proposal, reproachful, unsocial
4 Syllables: UUSU
anecdotal, antisocial, ceremonial, matrimonial, sacerdotal, testimonial
5 Syllables: UUUSU
Constantinople

Found 54 words across 6 groupings. Skipped 12 excess words of a similar stem.