2 syllables:
aescin, besson, betsson, bressan, bresson, cecin, chesson, ciesin, creson, cresson, decine, dessin, dressen, dress in, ehsan, escin, essen, esson, essonne, hessen, hesson, jessen, jesson, kessen, kesten, kressin, lesesne, lessen, lessin, lesson, less in, mesen, messan, messen, messene, messin, messin', mess in, pessin, pressen, presson, press in, stress in, szczecin, tessin, wessen, wesson, yesen, aisin, basen, base in, basin, beisan, blasen, brace in, case in, cayson, chacin, chaisson, chasen, chasten, clasen, face in, grace in, grayson, hasten, jasen, jason, klasen, leysen, mason, pace in, place in, race in, rasen, space in, spleisson, taisen, trace in, vasen, vasten

3 syllables:
aggressin, cavesson, clavecin, dance lesson, distress in, expressen, express in, fluorescin, french lesson, golf lesson, luc besson, mckesson, monesin, monessen, possess in, prinzessin, putrescin, recess in, smif-n-wessun, success in, taliessin, unless in, vergessen, abblasen, acrasin, agrasen, belasten, bombasin, bombasine, briefkasten, capsaicin, catch-basin, disseisin, freemason, grandmaison, handbasin, jamaicine, nick mason, salveson, sandkasten, slop basin, stonemason, washbasin

4 syllables:
abendessen, acquiesce in, argipressin, camptothecin, desmopressin, felypressin, german lesson, hebrew lesson, language lesson, music lesson, object lesson, ornipressin, tennis lesson, terlipressin, vasopressin, abgerissen, aufgeblasen, david jason, drainage basin, freddy vs. jason, gustaveson, jackie mason, river basin, tidal basin, zettelkasten

5 syllables:
cartier-bresson, delicatessen, delikatessen, history lesson, kristoffer klaesson, nevertheless in, piano lesson, violin lesson, abfasen, indomethacin

1 syllable:
corp

2 syllables:
nation, leaven, station, nathan, devon, raven, haven, shaven, blazon, heaven, stetson, kazan, haitian, brazen, deafen, suasion, freshen, question, session, resin, hazan, thracian, asian, ration, evan, seven, maven, cession, craven, cation, hessian, graven, haitien

3 syllables:
corrasion, lunation, relation, mentation, ligation, illation, pronation, creation, purgation, serration, invasion, fixation, succession, agnation, alsatian, progression, suppression, foundation, duration, proration, bull session, night raven, migration, rogation, causation, sedation, secession, sea raven, palpation, vacation, persuasion, stagnation, location, temptation, flotation, transgression, malaysian, castration, damnation, donation, rotation, hydration, crustacean, citation, oblation, lactation, repression, probation, selachian, plication, compression, frustration, vexation, cetacean, inflation, recession, formation, salvation, summation, abrasion, emblazon, digression, gradation, dilation, dissuasion, dictation, enation, eleven, evasion, planation, jactation, notation, reflation, new haven, regression, furcation, legation, expression, cremation, concession, gum resin, gas station, gyration, confession, taxation, carnation, prostration, croatian, translation, ovation, libation, plantation, sensation, lavation, outstation, gustation, aggression, filtration, cunctation, striation, unshaven, procession, jam session, oration, potation, pervasion, aeration, stagflation, collation, gestation, negation, occasion, possession, impression, placation, pulsation, titration, vocation, depression, vibration, obsession, profession, starvation, flirtation, chelation, predation, dalmatian, deflation, privation, accession, space station, caucasian, cessation, precession, egression, cognation, floatation, oppression, quotation, ablation, mutation, elation, discretion, nutation, luxation, solvation, equation, narration, closed session, phaethon, rap session, refreshen, skull session, afrasian, aid station, air station, bus station, c-ration, clean-shaven, coach station, fellation, lusatian, pay-station, septation, shore station, smooth-shaven, spoilation, testacean, train station, well-shaven

4 syllables:
distillation, service station, exaltation, incarnation, personation, propagation, incitation, transformation, wave equation, carbonation, escalation, crenelation, indignation, litigation, preparation, execration, desperation, abjuration, perpetration, ulceration, estimation, fractionation, transportation, subluxation, weather station, dislocation, attestation, solmization, dispensation, hibernation, constipation, convocation, commutation, pollination, calibration, self-expression, illustration, special session, subornation, orchestration, procreation, derivation, inflammation, instillation, fecundation, murmuration, scintillation, motivation, fulmination, conversation, registration, reputation, publication, violation, captivation, instigation, proclamation, avocation, molestation, masturbation, malformation, petrol station, satiation, fomentation, castigation, exploration, supination, enervation, population, declination, presentation, loan translation, divagation, delegation, expurgation, indication, ambulation, peroration, machination, revocation, observation, fascination, recitation, emigration, consultation, fumigation, desolation, extrication, reprobation, deportation, tessellation, lubrication, stimulation, sustentation, inculcation, abnegation, graduation, levitation, liquidation, medication, induration, implication, visitation, legislation, consternation, regulation, transplantation, nonaggression, saturation, filiation, mitigation, stridulation, gastrulation, decompression, conjugation, operation, suffocation, disinflation, variation, invocation, mediation, imprecation, designation, decoration, denudation, corrugation, corporation, incubation, denigration, police station, termination, abrogation, fluoridation, reservation, perspiration, formulation, granulation, infiltration, maculation, spoliation, perturbation, sanitation, equitation, habitation, urtication, coarctation, defalcation, realization, relegation, intercession, detestation, palpitation, consummation, excavation, foliation, automation, resignation, obfuscation, retardation, declaration, suppuration, meditation, amputation, affirmation, translocation, divination, peculation, pullulation, cancellation, inspiration, usurpation, occupation, instauration, disputation, adjuration, ostentation, emendation, emanation, flagellation, palliation, tabulation, permutation, chlorination, destination, admiration, germination, application, elongation, annotation, vegetation, reformation, fermentation, dilatation, cannulation, recusation, agitation, exhalation, computation, misquotation, ablactation, ideation, alteration, mensuration, jubilation, claudication, consolation, arbitration, revelation, syndication, dissertation, transpiration, aggravation, lamentation, desecration, adaptation, malversation, bifurcation, profanation, commination, incrustation, delectation, fragmentation, complication, flocculation, iteration, deformation, confiscation, contemplation, restoration, ministration, prorogation, inundation, aviation, intonation, calcination, generation, arrogation, exploitation, jactitation, ululation, aspiration, allegation, vaccination, fire station, calculation, derogation, tree of heaven, realisation, melioration, accusation, defamation, botheration, moderation, dispossession, speculation, maceration, concentration, implantation, culmination, subjugation, cogitation, expectation, sternutation, exhumation, collocation, insolation, actuation, fluctuation, heat prostration, hyphenation, trifurcation, separation, eructation, protestation, lachrymation, reclamation, mastication, inclination, expiation, consecration, placentation, depredation, inculpation, coronation, condemnation, imbrication, auscultation, condonation, conflagration, renovation, domination, transmigration, fibrillation, transmutation, trephination, congregation, retrogression, dehydration, obviation, education, duplication, titillation, connotation, crepitation, sublimation, intimation, osculation, deprivation, indentation, cerebration, respiration, transudation, sporulation, imputation, embrocation, salutation, navigation, affixation, excitation, nomination, herniation, estivation, maturation, capitation, formication, filling station, appellation, confirmation, supplication, emulation, compensation, degradation, gemination, ordination, ovulation, provocation, adulation, installation, recreation, oxidation, demarcation, sequestration, augmentation, combination, approbation, objurgation, insulation, mutilation, information, acclamation, indexation, exultation, inhalation, menstruation, activation, explication, reparation, pagination, impregnation, declamation, deprecation, deviation, animation, radiation, embarkation, prepossession, ruination, annexation, vindication, glaciation, rumination, allocation, metrication, conservation, obligation, inhumation, punctuation, constellation, mistranslation, compilation, preservation, simulation, penetration, angulation, adoration, condensation, seventh heaven, denotation, predication, cultivation, conformation, irrigation, lamination, acclimation, celebration, power station, dedication, incantation, quantization, promulgation, supersession, liberation, blood relation, re-creation, valuation, tribulation, elevation, assignation, strangulation, salivation, limitation, tax evasion, detonation, speciation, confrontation, toleration, comfort station, inspissation, aestivation, isolation, immigration, refutation, aberration, segmentation, devastation, crenellation, evocation, point mutation, exculpation, exhortation, exportation, infestation, postulation, impartation, hesitation, lineation, prolongation, veneration, lacrimation, encrustation, numeration, demonstration, innovation, federation, extirpation, modulation, repossession, stipulation, explanation, indiscretion, urination, altercation, correlation, abdication, defecation, debarkation, aggregation, pigmentation, segregation, fornication, integration, situation, gravitation, dissipation, fabrication, exudation, validation, coloration, trepidation, insufflation, great depression, expiration, acceptation, vitiation, confutation, exclamation, ventilation, imitation, recantation, commendation, relaxation, contestation, vacillation, relocation, conjuration, irritation, copulation, conurbation, brachiation, undulation, figuration, invitation, importation, affectation, laceration, oscillation, deputation, perforation, replication, deaccession, health profession, learned profession, practice session, self-possession, sense impression, twenty-seven, vault of heaven, vinyl resin, wage concession, affrication, asian nation, back-formation, balkan nation, canulation, co-optation, constatation, cuspidation, dessication, dressing station, factorisation, gene mutation, in-migration, lookout station, lucubration, miscreation, nganasan, on occasion, out-migration, paid vacation, pair creation, pair formation, peptization, pollenation, polling station, pumping station, quantisation, raft foundation, railroad station, railway station, remote station, sampling station, skin sensation, social station, solmisation, stylisation, stylization, subway station, taste sensation, touch sensation, tv station, vacuolation

5 syllables:
neutralisation, origination, inosculation, socialisation, polish notation, dissociation, novelization, expatriation, amalgamation, prevarication, machine translation, self-preservation, confabulation, examination, transamination, equivocation, civilization, facilitation, cooperation, discoloration, predestination, reverberation, harmonization, humiliation, expropriation, obliteration, vaporization, phenolic resin, subordination, memorization, colonization, retaliation, ossification, accommodation, prefix notation, congratulation, close corporation, classification, radio station, purification, factorization, melamine resin, pulverization, dramatization, expostulation, concatenation, symbolization, privatization, tergiversation, gratification, vocalization, standardisation, complementation, metrification, alleviation, exaggeration, cauterisation, standing ovation, divarication, agglutination, exacerbation, closed corporation, canalisation, multiplication, digitization, modification, fructification, centralization, decrepitation, degeneration, aftersensation, disinformation, mean deviation, discrimination, normalization, evaporation, ejaculation, regimentation, facial expression, invigoration, habituation, rectification, monetization, syllabication, magnetization, nitrification, fossilization, mummification, soil conservation, delimitation, beautification, manic depression, coeducation, fortification, de-escalation, elaboration, adulteration, hybridisation, interpellation, colonisation, peregrination, mobilisation, appreciation, magnification, epoxy resin, inoculation, urbanization, preoccupation, localization, repatriation, elicitation, vulcanization, sanitization, capitulation, maximization, reforestation, echolocation, synthetic resin, fertilization, contraindication, stultification, notification, emancipation, extenuation, synchronization, typification, elucidation, organization, sanitisation, cauterization, corroboration, alienation, stabilization, devaluation, visualization, theorization, petrification, impersonation, domestication, consideration, approximation, rationalisation, elimination, nasalization, procrastination, participation, denunciation, orientation, appropriation, abomination, oxidization, remuneration, penalization, excogitation, idealisation, solarization, denomination, authorization, focalization, invagination, perambulation, recommendation, acrylic resin, disembarkation, resuscitation, hybridization, randomization, vilification, equalization, emasculation, infatuation, clarification, prefiguration, federalization, canonization, pauperization, assimilation, bastardisation, crystallization, dramatisation, unionisation, articulation, falsification, neutralization, calcification, revaluation, depreciation, commemoration, vulcanisation, transliteration, effectuation, randomisation, phase modulation, virilization, continuation, renunciation, verbalization, mystification, self-flagellation, abbreviation, unionization, westernization, sterilization, irradiation, anticipation, sophistication, channelization, sanctification, superfetation, dissimilation, expectoration, specialisation, indoctrination, victimization, desegregation, deregulation, tubal ligation, substantiation, illumination, prognostication, investigation, reciprocation, nationalisation, inauguration, debilitation, imagination, ratification, deification, regeneration, extermination, mollification, vociferation, excruciation, insemination, atomisation, modernization, synchronisation, fasciculation, invalidation, solemnization, negotiation, finalization, communication, certification, disintegration, jollification, reincarnation, alimentation, sensitisation, foreordination, immoderation, defibrillation, ramification, legalization, confederation, disinclination, amplification, evaluation, pasteurization, justification, misinformation, columniation, defoliation, inhabitation, centrifugation, perpetuation, recuperation, pronunciation, densification, representation, polarization, intercalation, felicitation, discolouration, cohabitation, incrimination, accentuation, x-radiation, vaporisation, shell corporation, interpretation, acceleration, miscegenation, inactivation, reiteration, enumeration, extrapolation, pulse modulation, mobilization, beat generation, sedimentation, recrimination, minimization, precipitation, accreditation, exasperation, repudiation, determination, sensitization, documentation, organisation, deceleration, anovulation, eradication, canalization, incarceration, vulgarization, interrelation, argumentation, solicitation, regurgitation, authorisation, amortization, stigmatization, incorporation, ornamentation, collaboration, exoneration, idolization, interrogation, accumulation, conglomeration, contamination, agglomeration, immunisation, remediation, nullification, specification, perseveration, miscalculation, reduplication, attenuation, fraternization, predomination, interpolation, proliferation, edification, implementation, signification, transfiguration, initiation, improvisation, reification, subsidization, sterilisation, atomization, delineation, insinuation, emaciation, gasification, afforestation, vitrification, supplementation, intimidation, deforestation, premeditation, amelioration, dissimulation, unification, qualification, misapplication, dissemination, simplification, authentication, disinfestation, consolidation, coagulation, vivification, intoxication, stratification, desalination, amortisation, assassination, asphyxiation, vacuolization, specialization, iodination, utilisation, immunization, crystallisation, instrumentation, versification, standardization, adjudication, evacuation, triangulation, subpopulation, exhilaration, localisation, despoliation, republication, self-pollination, carbonization, affiliation, quantification, harmonisation, conciliation, visualisation, rejuvenation, administration, bastardization, normalisation, disapprobation, decapitation, polarisation, vasodilation, manipulation, stabilisation, heat of formation, inebriation, glorification, fertilisation, utilization, mechanization, oxygenation, humanization, pacification, demodulation, ionization, vituperation, manifestation, coordination, annihilation, annunciation, verification, legalisation, codification, refrigeration, prefabrication, association, hallucination, asseveration, grade separation, modernisation, deliberation, socialization, configuration, centralisation, amino resin, cannabis resin, image compression, legal profession, line of succession, manna from heaven, natural resin, silicone resin, simple regression, taking possession, transferred possession, without expression, acculturation, across the nation, african nation, alluviation, barbarisation, barbarization, bowdlerisation, brutalisation, business relation, cannulization, canonisation, canulization, carbonisation, change of location, channelisation, communisation, communization, cross-pollination, de-iodination, deactivation, dilapidation, direct quotation, disforestation, enthronization, enunciation, finalisation, fluoridization, focalisation, formalisation, fraternisation, gasoline station, gesticulation, glamorization, humanisation, idolisation, infrigidation, invigilation, in operation, in that location, itemisation, job application, legal relation, loan application, magnetisation, matriculation, maximisation, mechanisation, minimisation, misestimation, monetisation, motorisation, motorization, nervous prostration, novelisation, officiation, oil conservation, oxidisation, painful sensation, partner relation, pervaporation, phi correlation, plagiarisation, plagiarization, prechlorination, preordination, pressure sensation, private foundation, propitiation, pulverisation, rate of inflation, reallocation, rededication, refabrication, reticulation, ruggedisation, ruggedization, scandalisation, scandalization, schematisation, schematization, self-abnegation, self-accusation, self-condemnation, self-contemplation, self-cultivation, self-education, self-realisation, self-reformation, set decoration, sex segregation, signalization, skew correlation, social occasion, social relation, spatial relation, star divination, stigmatisation, subsidisation, suffix notation, summarization, tactile sensation, tenderization, terrorisation, terrorization, theorisation, trust corporation, vaticination, veiled accusation, verbal creation, vermiculation, viatication, victimisation, vulgarisation, wind generation, with inspiration, with moderation, with ostentation, with speculation

6 syllables:
harmonic progression, solidification, special education, nonproliferation, overpopulation, reclassification, rehabilitation, syllabification, hospitalization, secularization, overcompensation, disorientation, liberalization, internalization, popularization, regularization, linear equation, individuation, axis of rotation, devitalization, multiple regression, mental reservation, solar radiation, undervaluation, mental retardation, nitrogen fixation, decimalization, polymerisation, private corporation, disassociation, misinterpretation, alphabetization, self-organization, objectification, detoxification, superannuation, free association, personification, disqualification, self-annihilation, cross-fertilization, disorganization, capitalisation, reexamination, clinical depression, complement fixation, psychotic depression, democratization, consubstantiation, acidification, law of gravitation, standard deviation, misrepresentation, decentralization, secularisation, externalisation, decontamination, indemnification, intermediation, misappropriation, serialization, prestidigitation, polymerization, reactive depression, categorization, revivification, adult education, self-gratification, extemporization, experimentation, insubordination, commercialization, differentiation, acclimatization, identification, intensification, diversification, supererogation, radiolocation, collectivization, actualisation, actualization, acclimatisation, declassification, desensitization, autoregulation, board of education, revitalization, incoordination, reconciliation, self-fertilization, demobilization, initialization, heat of condensation, nationalization, alphabetisation, desensitisation, ammonification, familiarization, higher education, homogenisation, hospitalisation, discontinuation, inside information, categorisation, gamma radiation, alpha radiation, executive session, naturalisation, reorientation, monopolization, demoralization, transmogrification, excommunication, generalization, counter reformation, law of segregation, transubstantiation, beatification, serialisation, self-determination, demonetization, predetermination, reorganization, neurotic depression, animalization, overvaluation, logical relation, recapitulation, immobilisation, ratiocination, beta radiation, externalization, characterization, federalisation, water of hydration, desalinization, linear regression, superfecundation, demagnetization, idealization, electrification, capitalization, saponification, beneficiation, reunification, immunosuppression, inconsideration, regression equation, exemplification, vacuum aspiration, digitalization, background radiation, reconsideration, blood coagulation, naturalization, conceptualisation, self-justification, cross-examination, legal separation, personal equation, workmen's compensation, rationalization, dehumanization, immobilization, indirect expression, medical profession, natural depression, polyvinyl resin, retarded depression, thermoplastic resin, thermosetting resin, abarticulation, active application, animalisation, artistic creation, astronavigation, auto limitation, binary notation, bowdlerization, broad interpretation, bush administration, change orientation, chemical notation, circularisation, circularization, circumnavigation, collectivisation, commercialisation, control operation, covert operation, credit application, cross-classification, cross-fertilisation, cryptic coloration, daily variation, decentralisation, decimalisation, decimal notation, decolonisation, decolonization, dehumanisation, demobilisation, democratisation, demonetisation, desalinisation, desynchronisation, desynchronization, detribalisation, detribalization, devitalisation, de jure segregation, dichotomisation, dichotomization, digitalisation, direct correlation, domiciliation, dust contamination, eternal damnation, european nation, exponentiation, extemporisation, feast of dedication, fictionalisation, fictionalization, field of operation, giving medication, group participation, hyalinization, hyperventilation, hypostatisation, hypostatization, indetermination, infantile fixation, in collaboration, lecture demonstration, liberalisation, line organization, linguistic relation, loan participation, logic operation, machine operation, magnitude relation, masculinization, medical relation, militarisation, militarization, mispronunciation, missionary station, monopolisation, moral obligation, mortgage application, musical notation, mythologisation, mythologization, naval installation, neutron radiation, non-discrimination, nonparticipation, observation station, oral presentation, organification, overestimation, overexploitation, overt operation, partial correlation, part to whole relation, patent application, personal relation, popularisation, printing operation, public presentation, racial segregation, re-afforestation, reaffiliation, redetermination, reevaluation, regularisation, reharmonization, reinterpretation, reorganisation, revitalisation, romanticisation, romanticization, sectionalization, self-depreciation, self-examination, self-fertilisation, self-incrimination, self-mortification, self-organisation, self-realization, self-renunciation, semantic relation, sexual relation, superordination, swiss confederation, systematisation, systematization, television station, temporal relation, threshold operation, tintinnabulation, underestimation, unsanctification, visual sensation, warning coloration, water conservation, whole to part relation, without moderation, with consideration, with determination, world organization

7 syllables:
materialization, miniaturization, closely held corporation, protective coloration, demineralization, visible radiation, diagonalization, agitated depression, fractional distillation, geometric progression, social organization, industrialization, intercommunication, vertical integration, industrialisation, materialisation, magnetic levitation, magnetic variation, infrared radiation, spherical aberration, physical education, positive correlation, differential equation, arithmetic progression, binary operation, sympathetic vibration, criminal conversation, particularization, written communication, oral examination, acid precipitation, angle of inclination, celestial navigation, ultracentrifugation, telecommunication, denationalization, world health organization, insider information, reverse polish notation, frequency modulation, destructive distillation, americanization, amplitude modulation, suspended animation, spiritualization, heat of vaporization, economics profession, exogenous depression, exponential expression, material possession, academic relation, anticoagulation, antitrust legislation, auditory sensation, baptist denomination, bioremediation, business organization, by experimentation, carter administration, clandestine operation, clinton administration, cognitive operation, computer operation, concrete representation, concurrent operation, conditional relation, conventionalisation, conventionalization, dark field illumination, dark ground illumination, data communication, dedifferentiation, demand for explanation, demythologisation, demythologization, denationalisation, de facto segregation, diurnal variation, doctor of education, electron radiation, europeanization, exponential equation, exteriorisation, exteriorization, feast of the dedication, final examination, financial obligation, fourfold point correlation, grammatical relation, guilt by association, heat of dissociation, indian reservation, indirect correlation, inertial navigation, judicial separation, kendall rank correlation, legal representation, logical implication, logical operation, lukasiewicz notation, magnetic inclination, master of education, memorialisation, memorialization, mental representation, midterm examination, military formation, miniaturisation, multiplex operation, natural elevation, negative correlation, negative stimulation, north american nation, olfactory sensation, optical aberration, oral communication, overutilisation, overutilization, parallel operation, philanthropic foundation, physical restoration, point of accumulation, police investigation, political relation, practical application, professional relation, pseudohallucination, psychic communication, racial extermination, radio observation, radio radiation, rate of acceleration, rate of depreciation, reagan administration, remilitarization, right of first publication, scandinavian nation, selective information, sentimentalisation, sentimentalization, sequential operation, serial operation, serial publication, software documentation, source of illumination, south american nation, spiritualisation, spurious correlation, surface assimilation, surgical operation, telephone conversation, underevaluation, under consideration, unspoken accusation, value orientation, vertical combination, victory celebration, without consideration

8 syllables:
unemployment compensation, animal communication, war of the spanish succession, artificial respiration, vocational education, postmortem examination, internationalisation, aegean civilization, spontaneous generation, horizontal integration, character assassination, interior decoration, department of education, behavior modification, internationalization, overcapitalization, holy day of obligation, ventricular fibrillation, individualization, letters of administration, department of transportation, chronological succession, ecological succession, idiomatic expression, amphibious demonstration, amphibious operation, arithmetic operation, asynchronous operation, auxiliary operation, cardiac resuscitation, cartilaginification, central american nation, ceremonial occasion, confidential information, consecutive operation, digital communication, economic strangulation, elementary education, enabling legislation, fiduciary relation, financial organization, freedom from discrimination, geological formation, horizontal combination, intelligence operation, internal representation, linguistic communication, literal interpretation, majority operation, mathematical notation, mathematical relation, medical examination, military installation, minoan civilization, musical organization, newton's law of gravitation, nonlinear correlation, privately held corporation, protestant denomination, psychical communication, radiocommunication, religious orientation, secondary education, symbolic representation, territorialisation, territorialization, visual communication

9 syllables:
ultraviolet radiation, war of the austrian succession, articles of incorporation, coefficient of correlation, proportional representation, partial differential equation, savings and loan association, health maintenance organization, hydrogen ion concentration, artificial insemination, anabaptist denomination, anomalous communication, auditory communication, demand for identification, economic mobilization, electronic communication, el nino southern oscillation, kendall partial rank correlation, mathematical operation, mycenaean civilization, myocardial inflammation, pecuniary obligation, physical rehabilitation, pictorial representation, political orientation, professional association, reasoning by elimination, secretary of education, secretary of transportation, simultaneous operation, through empirical observation

10 syllables:
federal housing administration, certificate of incorporation, electromagnetic radiation, correctional rehabilitation, international organization, preliminary examination, therapeutic rehabilitation, ultraviolet illumination, vocational rehabilitation

11 syllables:
federal home loan mortgage corporation, food and agriculture organization, north atlantic treaty organization, international finance corporation, social security administration, federal bureau of investigation, binary arithmetic operation, paramilitary organization

12 syllables:
cardiopulmonary resuscitation, international labor organization, international labour organization, simulated military operation

13 syllables:
federal national mortgage association, federal deposit insurance corporation, international maritime organization, world meteorological organization

14 syllables:
international development association, national aeronautics and space administration

16 syllables:
international civil aviation organization

23 syllables:
united nations educational scientific and cultural organization