2 Syllables: SU
Belgian, Belgium, bellum, Cheltenham, Ellen, felon, Helen, melon, Nelson, Nelson's, Pelham, Selden, seldom, Sheldon, twelvemonth, vellum, welcome, Wesleyan
3 Syllables: USU
4 Syllables: UUSU

Found 23 words across 3 groupings. Skipped 5 excess words of a similar stem.