2 syllables:
mental, mentale, cental, dental, dentale, dentil, dentile, ental, gentle, kentle, lentil, lentille, pentyl, rental, sentell, trental, ventil, ventile, yentl

3 syllables:
momental, again till, amental, argental, bidental, cemental, ectental, fermental, judgemental, judgmental, omental, parental, pigmental, pimental, placental, proventil, regental, simental, simmental, submental, tangental, tegmental, the rental, tormentil, ungentle

4 syllables:
monumental, nidamental, accidental, alimental, apartmental, aplacental, argumental, atramental, biparental, circumlental, compartmental, complemental, complimental, condimental, continental, decremental, departmental, detrimental, documental, elemental, excremental, experimental, falcon-gentle, firmamental, flower-gentle, fondamentale, fundamental, governmental, implacental, implemental, incendental, incidental, incindental, incremental, instrumental, interdental, interdentil, isopentyl, linguadental, linguidental, managemental, nonjudgmental, nonsegmental, nutrimental, occidental, occidentale, oriental, orientale, ornamental, paradental, parliamental, pedimental, peridental, recremental, regimental, retrolental, rudimental, sedimental, sentimental, sentimentale, supplemental, temperamental, tenemental, testamental, thiopental, trancscendental, transcendental, transplacental, transsegmental, tunnelmental

5 syllables:
coincidental, developmental, dissepimental, emolumental, environmental, equimomental, fetoplacental, impedimental, inalimental, integumental, intersegmental, labiodental, labiomental, lineamental, maxillodental, non-governmental, nongovernmental, pancontinental, presentimental, subcontinental, suprasegmental, transcontinental, uniparental, unornamental, unsentimental

6 syllables:
alveolodental, epicontinental, intercontinental, interdepartmental, intergovernmental, intradepartmental, occipitomental, uteroplacental

7 syllables:
bioenvironmental

2 syllables:
bengal, kendall, mendel, temple, tremble

3 syllables:
ventricle, helical, despiteful, medical, denticle, festival, reticle, sceptical, vesicle, ethnical, pellicle, testicle, technical, metrical, plentiful, skeptical, besprinkle, ethical, pedicel, centrical, metical, epical, chemical, assemble, dissemble, provencal, resemble

4 syllables:
electrical, heretical, alchemical, unethical, prophetical, genetical, identical, nonsensical, extendible, ereshkigal, appendicle, calendrical, directional, aesthetical, symmetrical, ascetical, indelible, esthetical, angelical, putrescible, obstetrical, synthetical, bay of bengal, disassemble, gregor mendel, preassemble, reassemble

5 syllables:
parenthetical, homiletical, geometrical, petrochemical, imperceptible, exegetical, ecumenical, evangelical, diametrical, dialectical, hypothetical, unsymmetrical, catechetical, theoretical, oecumenical, asymmetrical, arithmetical, alphabetical, antithetical

6 syllables:
incomprehensible, infinitesimal, antipathetical, gregor johann mendel