Vietcong rhymes with:
cong, hong-kong, kong, 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, prolong, prong, pudong, quang, rong, sarong, see-kiong, song, spong, sprong, stong, strong, thong, throng, tong, truong, vong, vuong, wong, wrong, xiong, xudong, xuedong, yearlong, yong, yuzong, zedong