Mouthpiece rhymes with:
altarpiece, centerpiece, crosspiece, eyepiece, greenpeace, masterpiece, showpiece, timepiece, allweiss, altarpiece, buslease, centerpiece, crosspiece, eyepiece, greenpeace, irianese, legalese, masterpiece, petrosynthese, sangiovese, showpiece, sublease, syntheses, timepiece, viennese
Mouthpiece sounds like:
medaphis, medivac, metaphysics, metavsky, midpac, midpac's, midwives, mitofsky, modifies, montefusco, motifs, motives, mouthpieces