Prolong rhymes with:
along, delong, along, belong, delong, lifelong, long, yearlong, along, aung, belong, chong, cong, cuong, dejong, dejonge, dejongh, delong, dong, fong, gong, guangdong, hmong, hong, hong-kong, jong, kong, kwong, kyong, kyoung, lifelong, long, luong, maung, mong, ong, phuong, pong, prong, pudong, quang, rong, sarong, see-kiong, song, spong, sprong, stong, strong, thong, throng, tong, truong, vietcong, vong, vuong, wong, wrong, xiong, xudong, xuedong, yearlong, yong, yuzong, zedong
Prolong sounds like:
paralleling, parlance, parlaying, paroling, pearling, perelman's, prelims, prolongs, prowling