There are 516 twelve-letter words containing A, D and 2T, https://www.bestwordlist.com/c/a/4/12letterwordswithadtt.htm
ABSINTHIATED ABSTRACTEDLY ACCULTURATED ACQUITTANCED ADAPTABILITY
ADAPTATIONAL ADAPTIVITIES ADDITIVITIES ADJUSTMENTAL ADMINISTRANT
ADMINISTRATE ADOPTABILITY ADOPTIANISTS ADOPTIONISTS ADSCITITIOUS
ADULTERATING ADULTERATION ADULTERATORS ADULTESCENTS ADVENTITIOUS
ADVENTURISTS AGGLUTINATED ALTITUDINOUS AMPHIDENTATE ANDOUILLETTE
ANECDOTALIST ANESTHETISED ANESTHETIZED ANTECEDENTLY ANTIADITISES
ANTICATHODES ANTIDIABETIC ANTIDILUTION ANTIDIURETIC ANTIDOGMATIC
ANTIOXIDANTS ANTIPREDATOR ARTIODACTYLS ASTOUNDMENTS ATTENDANCIES
ATTENDEMENTS ATTITUDINISE ATTITUDINIZE ATTORNEYDOMS AUDIOMETRIST
AUDIOTYPISTS AUDITABILITY AUTOANTIBODY AUTODESTRUCT AUTODIDACTIC
AUTOXIDATION BACKSTITCHED BASTARDLIEST BATTLEFIELDS BATTLEGROUND
BATTLEMENTED BODDHISATTVA BODHISATTVAS BOOTSTRAPPED CARROTTOPPED
CATADIOPTRIC CATHETERISED CATHETERIZED CERTIFICATED COADAPTATION
COCCIDIOSTAT COCULTIVATED CONCATENATED CONCENTRATED CONDITIONATE
CONSTELLATED CONSTERNATED CONSTUPRATED CONTAMINATED CONTEMPLATED
CONTRACTEDLY CONTRADICTED CONTRADICTER CONTRADICTOR COUNTERACTED
COUNTERTRADE DARMSTADTIUM DASTARDLIEST DEACTIVATING DEACTIVATION
DEACTIVATORS DEARTICULATE DEATHWATCHES DEATTRIBUTED DEATTRIBUTES
DEBILITATING DEBILITATION DEBILITATIVE DECANTATIONS DECAPITATING
DECAPITATION DECAPITATORS DECENTRALIST DECONGESTANT DECORTICATED
DECORTICATES DECORTICATOR DECREPITATED DECREPITATES DECRETALISTS
DECRUSTATION DEFENESTRATE DEFLATIONIST DEGLUTINATED DEGLUTINATES
DEGUSTATIONS DEHORTATIONS DELECTATIONS DELEGITIMATE DELIMITATING
DELIMITATION DELIMITATIVE DEMETHYLATED DEMETHYLATES DEMOCRATISTS
DEMONSTRATED DEMONSTRATES DEMONSTRATOR DEMOTIVATING DEMOTIVATION
DENATURATION DENITRATIONS DENOTATIVELY DENTICULATED DENTIROSTRAL
DEPARTEMENTS DEPARTMENTAL DEPORTATIONS DEPOSITATION DEPUTISATION
DEPUTIZATION DERMATITIDES DERMATITISES DERMATOPHYTE DESATURATING
DESATURATION DESTIGMATIZE DESTINATIONS DETERIORATED DETERIORATES
DETERMINANTS DETERMINATED DETERMINATES DETERMINATOR DETESTATIONS
DETONABILITY DETOXICATING DETOXICATION DETRACTINGLY DETRACTIVELY
DETRAINMENTS DETRIMENTALS DETRUNCATING DETRUNCATION DEUTERATIONS
DEUTOPLASTIC DEVASTATIONS DEVIATIONIST DEXTRALITIES DEXTROGYRATE
DEXTROROTARY DICTATORSHIP DICTATRESSES DICTYOPTERAN DIETETICALLY
DIGITISATION DIGITIZATION DILATABILITY DILATATIONAL DILATOMETERS
DILATOMETRIC DILETTANTISH DILETTANTISM DIPLOMATISTS DIRECTORATES
DISCEPTATION DISCEPTATORS DISINFECTANT DISINFESTANT DISINTEGRATE
DISINTRICATE DISMASTMENTS DISMUTATIONS DISORIENTATE DISPUTATIONS
DISPUTATIOUS DISSERTATING DISSERTATION DISSERTATIVE DISSERTATORS
DISTEMPERATE DISTILLATION DISTILLATORY DISTORTIONAL DISTRACTABLE
DISTRACTEDLY DISTRACTIBLE DISTRACTIONS DISTRAINMENT DISTRAUGHTLY
DISTRIBUTARY DISTURBATIVE DITHEISTICAL DITHELETICAL DITHYRAMBIST
DITRANSITIVE DITTOGRAPHIC DOCTRINALITY DOMESTICATED DOMESTICATES
DOMESTICATOR DONATISTICAL DRAMATURGIST DUBITATIVELY DYSAESTHETIC
EDITORIALIST EDUCATIONIST EDUTAINMENTS ENCULTURATED EUTHANATISED
EUTHANATIZED EXCORTICATED EXPECTORATED EXPEDITATING EXPEDITATION
EXPOSTULATED EXTERMINATED EXTRADITABLE EXTRADITIONS EXTRAPOLATED
EXTRAVAGATED EXTRAVASATED FAINTHEARTED FIANCHETTOED FLUIDEXTRACT
FLUTTERBOARD FOOTBREADTHS FRACTIONATED FRAGMENTATED FUNCTIONATED
GESTICULATED GONIATITOIDS GREATHEARTED GUESSTIMATED GUTTURALISED
GUTTURALIZED HALFWITTEDLY HEREDITAMENT HETERODACTYL HYDROPATHIST
HYDROSTATICS HYPOSTATISED HYPOSTATIZED HYPOTHECATED ILLUSTRATEDS
IMPENETRATED IMPOSTUMATED INADAPTATION INDENTATIONS INDETECTABLE
INDOCTRINATE INEXACTITUDE INFATUATEDLY INGRATITUDES INGURGITATED
INSTANTIATED INTERCALATED INTERDIALECT INTERDIGITAL INTERGRAFTED
INTERMEDIATE INTERPLANTED INTERPOLATED INTERRELATED INTERROGATED
INTERSTADIAL INTERSTRANDS INTERTANGLED INTERTIDALLY INTIMIDATING
INTIMIDATION INTIMIDATORS INTIMIDATORY INTURBIDATED INTURBIDATES
INVESTIGATED LANDAULETTES LATITUDINOUS LAUNDERETTES LEPTODACTYLS
LIGHTHEARTED MAINSTREETED MALCONTENTED MALTODEXTRIN MATHEMATISED
MATHEMATIZED MATRICULATED MEDITATIVELY METASTASISED METASTASIZED
METATHESISED METATHESIZED MIDLATITUDES MIDLITTORALS MISENTREATED
MISESTIMATED MITHRIDATISE MITHRIDATISM MITHRIDATIZE MULTIDENTATE
MULTIFACETED MULTITRACKED MUTTONHEADED NECESSITATED NONACTIVATED
NONATTENDERS NONAUTOMATED OBJECTIVATED OBTEMPERATED OCTAHEDRITES
OCTAPEPTIDES ODONTOBLASTS ODONTOMATOUS ORCHESTRATED ORTHODONTIAS
ORTHOPAEDIST OUTDATEDNESS OUTDISTANCED OUTDISTANCES OUTPOPULATED
OUTTRAVELLED OVERTHWARTED PAEDIATRISTS PAEDOBAPTIST PARTICIPATED
PEDANTOCRATS PENTADACTYLE PENTADACTYLS PENTADACTYLY PENTAHYDRATE
PENTAPEPTIDE PENTLANDITES PERICLITATED PERLUSTRATED PHOTOCATHODE
PHOTOSTATTED PLATITUDINAL PONTIFICATED POSTACCIDENT POSTDOCTORAL
POSTGRADUATE PREADMITTING PRECIPITATED PREDESTINATE PREFORMATTED
PREMEDITATED PREMEDITATES PREMEDITATOR PRIVATDOCENT PRIVATDOZENT
PROTRACTEDLY PROTUBERATED PTERODACTYLE PTERODACTYLS QUIDDITATIVE
RADIESTHETIC RATIOCINATED READAPTATION READJUSTMENT READMITTANCE
REATTRIBUTED RECULTIVATED REDINTEGRATE REGURGITATED REINTEGRATED
REITERATEDLY REMONSTRATED RENEGOTIATED REORIENTATED REPUNCTUATED
RESTIMULATED RESUSCITATED RETARDATIONS RETRANSLATED SATELLITISED
SATELLITIZED SCATTERGOODS SCINTILLATED SEQUESTRATED SHIRTWAISTED
SIDEROSTATIC SPATTERDOCKS STADDLESTONE STADIOMETERS STADTHOLDERS
STAIRSTEPPED STANDPATTERS STANDPATTISM STAPEDECTOMY STAYSTITCHED
STEDFASTNESS STEPDAUGHTER STIPENDIATED STIPENDIATES STOMATITIDES
STOMATODAEUM STONYHEARTED STOUTHEARTED STRAIGHTBRED STRAIGHTEDGE
STRAIGHTENED STRANGULATED STRIDULANTLY STRIDULATING STRIDULATION
STRIDULATORS STRIDULATORY STRINGHALTED SUBDEBUTANTE SUBSATURATED
SUPERFETATED SWEETHEARTED SYNDIOTACTIC SYSTEMATISED SYSTEMATIZED
TAUTOLOGISED TAUTOLOGIZED TAXIDERMISTS TEETERBOARDS TELEPATHISED
TELEPATHIZED TENDENTIALLY TENDINOPATHY TENDONOPATHY TESTICULATED
TETRACHORDAL TETRADACTYLS TETRADACTYLY TETRADRACHMA TETRADRACHMS
TETRADYMITES TETRAHEDRITE TETRAHEDRONS THEATERLANDS THEATRELANDS
THEATRICISED THEATRICIZED THERMOSTATED THIRDSTREAMS THITHERWARDS
THREADBAREST TOLBUTAMIDES TRABECULATED TRACHEITIDES TRACTORFEEDS
TRADESCANTIA TRADITIONARY TRADITIONERS TRADITIONIST TRADUCEMENTS
TRADUCIANIST TRAITORHOODS TRANSCENDENT TRANSDUCTANT TRANSDUCTION
TRANSDUCTORS TRANSITIONED TRANSLOCATED TRANSPLANTED TRANSUDATION
TRANSUDATORY TREPIDATIONS TREPIDATIOUS TRIANGULATED TRICUSPIDATE
TRIDACTYLOUS TRIPUDIATING TRIPUDIATION TRIRADIATELY TUBERCULATED
TURRICULATED ULTRADISTANT UNADULTERATE UNATTENUATED UNATTRIBUTED
UNCAPTIVATED UNCONTRACTED UNCULTIVATED UNDERSTATING UNDERSTRATUM
UNDERTENANTS UNDERTREATED UNDETECTABLE UNDETECTABLY UNDISTRACTED
UNEXTENUATED UNHABITUATED UNINTEGRATED UNPUNCTUATED UNSTIMULATED
UNSTRATIFIED UNTERMINATED UNTHREATENED UNTRANSLATED UNTRANSMUTED
UNVENTILATED VENDITATIONS WILDCATTINGS WITHDRAWMENT WITHSTANDERS
WITHSTANDING