2 Syllables: SU
arches, Arden, ardent, aren, arson, Aryan, Austrian, bargain, barges, Barton, carbon, Carleton, Carlton, Carmen, Carson, Carthage, cartridge, Charleston, Charlton, Clarkson, darken, Dartmouth, foreign, garden, garland, garment, guardian, harden, Harlem, Hartmann, hearken, jargon, margin, Marian, Markham, marshes, Marston, Martin, Martin's, parchment, pardon, parlance, parson, partridge, Sargent, sergeant, Serjeant, sharpen, Spartan, Yarmouth
3 Syllables: SUU
3 Syllables: USU
4 Syllables: UUSU

Found 58 words across 4 groupings. Skipped 22 excess words of a similar stem.