Or search: sioux, siouan
2 Syllables: SU
Buenos, Cato, credo, halo, Mayo, Pedro, Pharaoh, Plato, Plato's, rainbow, scapegoat, waistcoats, Zeno
3 Syllables: USU
Barbadoes, Diego, Horatio, octavo, potato, potatoes, tomato, tomatoes, tornado, volcano, volcanoes
4 Syllables: UUSU
Galileo
5 Syllables: UUSUU
Archipelago

Found 26 words across 4 groupings. Skipped 1 excess word of a similar stem.