One of them is "iota."
standardizing
That is a trick question. You can't make a four letter word using all five vowels.
euphony
Some four-letter musical instruments that contain three vowels are "ukulele" and "oboe." While "ukulele" has more than four letters, "oboe" fits the criteria perfectly with three vowels and four letters. Other examples include "lute" and "horn," but they contain fewer vowels.
The 8-letter word that contains four 'N's and the other four letters are all vowels is "announcer."
Some four letter words that have two vowels are:abetableacheacmeacneahemamenanteaveraxlebabebakebarebarebasebeadbeakbeambearbeatbeefbeenbeerbeetbidebikebiteblueboarboatboilbonebookbootboreboutbozobriecafecagecakecamecanecapecarecasecavecluecodecoedcoilcoincolacomacomeconecopecorecovecubecurecutedaledamedaredatadatedaubdazedeaddeafdealdeardeeddeemdeepdeerdelidemodialdicedimedinediredivadivedoledomedonedopedovedozedudedukedunedupeeachearlearneastechoecruedenedgeeditelseemiremitepicergoeveneverevilewerexamexitfacefadefailfairfakefamefarefatefaunfauxfazefearfeatfeedfeelfeetfetafetefeudfieffifefilefinefirefivefleafleefluefoalfoamfoilfootforefreefumefusegagagaingaitgalagalegamegapegategavegazegeargeargenegivegleegluegoadgoalgoalgoatgoesgonegoodgoofgoopgoregoutguruhailhairhalehaloharehatehaulhavehazeheadhealheaphearheatheedheelheirhereherohidehikehirehivehoaxhoboholehomehonehoodhoofhookhoophoothopehosehourhugehulaibexibisiconidleidolintoirisironisleitemjadejailjavajeerjivejoinjokejudojutekalekeelkeenkeepkenokilokitekiwikneekookkudolacelaidlainlairlakelamelanelatelaudlavalazeleadleafleakleanleapleekliarliceliedlienlifelikelimelimolinelionliveloadloafloamloanlobelocolodelogoloinlonelookloomloonlooplootlopeloreloseloudloutlovelubelugelureluteluxemacemademagimaidmailmaimmainmakemalemamamanemarematemaulmazemeadmealmeanmeatmeekmeetmemomenumeowmeremesametemicamicemikemilemimeminemiremitemoanmoatmodemoilmojomolemoodmoonmoormootmopemoremotemovemulemumumusemutenailnamenapenearneatneedneonniceninenodenoelnonenooknoonnopenosenotenounnovanudeoathodorogleogreoinkokraomenomitonceontooopsopalopenoralorcaorzoovaloveroxenpacepagepaidpailpainpairpalepanepapaparepatepavepeakpealpearpeatpeekpeelpeeppeerpeonpesopicapierpikepilepinepipepitapleapoempoetpokepoleponepopeporeposepucepukepumapurequadquayquidquipquitquizracerageraidrailrainrakeraperarerateraverazereadrealreamreaprearredoreedreefreekreelreinricerideriferilerimeriotriperiseriteroadroamroanroarroberoderoleroofrookroomrootroperoseroteroutroveruberuderuinrulerusesafesagasagesaidsailsakesalesamesanesarisavesealseamsearseatseedseekseemseenseepseershoesidesilosinesiresitesizesoaksoapsoarsodasofasoilsolesolosomesoonsootsoresoulsoupsourspuesuetsuitsuretabutacotailtaketaletametapetaretarotaxiteaktealteamtearteatteemteentheethoutidetiertiletimetinetiretoadtofutogatoiltometonetooktooltoottoretotetourtreetriotruetubatubetunatunetutuulnaundounituntouponurgeuservainvalevanevasevealveerveilveinvetovialviceviewvilevinevisavisevoidvolevotewadewadiwagewaifwailwaitwakewanewarewaveweakwealweanwearweedweekweepwerewheewhoawidewifewilewinewipewirewisewokewoodwoofwoolworewoveyeahyearyetiyogayokeyoreyouryulezealzerozetazitizonezoom
An eight letter word with three vowels using those letters is scavenge.Eight letter words with four vowels using those letters are agencies and envisage.
The word for vowels in greek is Φωνήεντα (fonee-e-nda).
21^4
isle,else,also,
queue
queue