On this page, “the five vowels” refers to a, e, i, o, u, and “the six vowels” refers to those letters plus the letter y.
Some all-vowel Hawaiian names for birds which are used in English are AO - Puffinus puffinus (Manx shearwater), UAU - Pterodroma phaeopygia (Dark-rumped Shearwater), OEOE - Oceanodroma castro (Harcourt's Storm-petrel), IO - Buteo solitarius (Hawaiian Hawk), OOAA - Moho bracatus, OU - Psittirostra psittacea.
Allowing proper nouns, some words consisting only of vowels include AIEA (a city in Hawaii), EIAO (one of the Marquesas Islands), EA (a town in the Basque section of Spain), AEAEA (the legendary home of Circe in the Tyrrhenian Sea), AAUAUA (a river in Brasil), II (a place in Finland 40 km north of Oulu), and OUEOI (an ancient Tuscan city in Etruria). IO is the only name on any hurricane name list which consists entirely of vowels. It is on the Central Pacific hurricane name list [Brett Brunner, Juozas Rimas, Stuart Kidd, Pertti Malo]. Dmitri Borgmann gives OEAEI (the name of the wife of Ra-amen, the spondist of Pthah) [An Archaic Dictionary, From the Egyptian, Assyrian, and Etruscan Monuments and Papyri, by William R. Cooper, London, 1876]. OUADI EL AOUAOUIYE is a location in Syria, AOUEOUA in Mauritania, and AOUEOUE in Togo [Rex Gooch].
Allowing Y as a vowel, some words consisting only of vowels include AYE, AYU, EYE, IYO, EYEY, and YAYA (although I am not sure which of these Y's are vowels!).
The Hawaiian word HOOIAIOIA (meaning "certified") has eight consecutive vowels and is listed in the 1976 Guinness Book of World Records [Charles Turner].
Allowing proper nouns, IJOUAOUOUENE, a mountain in Morocco, has 8 consecutive vowels as rendered by the French [Guinness]. Also with 8 consecutive vowels are the Bled El HAOUAOUIA area and OUAOUIOUST hill (both in Morocco), AGUINAOUIAOUI in Mali, and ISSOUOUAOUAR in Niger [Susan Thorpe]. In Estonian, ÕUEAIAÄÄR means "edge of a fence surrounding a yard" [Juozas Rimas, Ahto Truu].
OUAOUIATON appears on a French map of the central part of North America printed in 1693, and has 7 consecutive vowels. The word was later shortened to OUAOUIA, and was applied to the Indian tribe subsequently called Iowa. [The Book of Names, J. N. Hook.] Other place names with 7 vowels in a row include AOUEOUA, (Mauritania), AOUEOUE, Togo, BOUAAOUAM (Algeria), TIOUOOUORT (Mali), and ES ZOUAOUIINE and TAZOUOUOUARHT (Morocco) [Susan Thorpe, Rex Gooch].
In Dutch, KOEIEUIER (the udder of a cow) and PAPEGAAIEËIEREN (parrot eggs) have seven consecutive vowels, although they are no longer valid spellings, having been replaced by KOEIENUIER and PAPEGAAIENEIEREN [Joost Gestel, Tom Vernooij, John Slegers].
Words with six consecutive vowels include EUOUAE, which W2 defines as "A word formed from the vowels of seculorum amen, ending the Gloria Patri," AIOUEA (a genus of plants of the laurel family), and DIOOEAE (a tribe of cycads) [Charles Turner].
The ZOUAOUA are a Kabyli tribe living in Algeria and Morocco. UAIEUE (variants: UAIUAI, WAIWAI or OUAYEONE) is a language of Brazil indians. AAUAUA is a river in Brasil. These words have 6 consecutive vowels [Juozas Rimas]. Also with six consecutive vowels is INOEIOIO in Mozambique [Susan Thorpe].
The Dutch word ZAAIUIEN (onions for seeding) has 6 consecutive vowels, still valid in the new spelling since 1995, although this is not found in the Van Dale dictionary [Oscar van Vlijmen].
Words with five consecutive vowels include QUEUEING, the interjection AIEEE, which is in the OED, and COOEEING. (COOEE or COOEY, a peculiar cry of the Australian aborigine, is in W1, W2, and W3. The word is also a verb and both W1 and W2 show the forms COOEEING and COOEEYING.) The OED2 has COUUIENALES, which is a variant of quienals, which comes from quiennal, meaning "dispensation or indulgence for five years." Other such words are MIEAOU (OED) and MIAOUED and MIAOUING (what a cat does; OSPD and Webster's Collegiate Dictionary, 5th edition), ZAOUIA (an alternate spelling of zawiya according to the OED2 - Jeremy Marshall), JUSSIEUEAN ("pertaining to the natural system of botanical classification devised by Bernard de Jussieu and his nephew Antoine Laurent de Jussie" [W3]) and ZOOEAE (larvae of crabs and relatives [Chris Cole]) or ZOAEAE [OED]. The Kaula (Pteralyxia kauaiensis) and the Holei (Ochrosia kilaueaensis) are endangered Hawaiian plants, and the Formosan Sika (Cervus nippon taiouanus) is an endangered Taiwanese deer. MIOEUOTICUS is a primate genus. Cyclostremiscus beauii is a Marine snail from Florida and Chicoreus beauii is Beau’s murex sea snail [Charles Turner, Philip Bennett].
The entomologist A. A. Girault named a group of tiny wasps for writers, scientists, statesmen, and philosophers (Shakespearia, Beethovena, Goetheana, Marxella, etc.). He named a wasp genus THOREAUIA for Henry David Thoreau. This word has five consecutive vowels [Charles Turner].
Some words with four consecutive vowels follow (although in some of these words the Y may not actually be a vowel): aqueous, Archaeoastronomy, Archaeoindris fontoynonti (an extinct species of lemur), Aysheaia ( fossil onychophoran), ballyhooey, bayou, biyearly, buoyance, buoyancy, buoyant, buoyed, buoying, clayey, dequeue, dequeuing, employee, enqueue, eyeing, flooey, Gnaoua (a Moroccan ethnic minority group and part of the name of the Gnaoua & World Music Festival which is held annually in Essaouira, Morocco, which also has four consecutive vowels), gooey, guaiacum, Hawaiian, hooey, joyous, kayoed, kayoing, layout, layouts, maieutic, obloquious, obsequious, onomatopoeia, palaeoanthropic, palaeoanthropology, Paraguayan, payee, pharmacopoeia, prosopopoeia, Quaoar (a term in the creation mythology of the Tongva people and a Kuiper Belt object discovered in 2002), quayage, queue, radioautograph, reliquiae, royaux, Rubaiyat, Sequoia, subaqueous, terraqueous, Uruguayan, Vegavis iaai (Late Cretaceous bird from Antarctica), voodooienne, voyeur, Yaounde [Nelson H. F. Beebe, Charles Turner, Paul Wright].
These words begin with four consecutive vowels: UEUETEOTL (an Aztec god), EUAECHME (a character in Greek mythology), and AEAETES (a character in Greek mythology) [Charles Turner].
Seven-letter words with the five vowels in any order are SEQUOIA, EULOGIA, EUNOIA (alertness of mind and will), MIAOUED, ADOULIE, EUCOSIA, EUNOMIA, EUTOPIA, MOINEAU, DOULEIA (an alternate spelling of DULIA which appears in W2), and EUODIAS (a name in Philippians 4:2). Allowing scientific names in biology, IOUEA is a genus of Cretaceous fossil sponges. BOIEAU is a town in Belgium. POAEUI Passage is in Papua New Guinea [Philip Bennett, Susan Thorpe, Stuart Kidd, Rex Gooch].
Eight-letter words with the five vowels in any order are AEGOLIUS (a genus of owls), AEQUORIN, AEROBIUM, AGOUTIES, DIALOGUE, EDACIOUS, EQUATION, EULOGIAS, EUPHORIA, EUSOCIAL, EXONUMIA, JALOUSIE, OUTRAISE, SAUTOIRE, SEQUOIAS, and THIOUREA [Philip Bennett, Charles Turner].
Eight-letter words containing the six vowels in any order are IALOUSYE, EURYOPIA, EYDOUXIA, EURYOMIA, EUMYOBIA, and JOYEUXIA [Stuart Kidd].
Nine-letter words containing the six vowels in any order are OXYURIDAE (pinworms), OXYGEUSIA (abnormal sensitivity to taste), LOUISELLA (a genus of fossil priapulid worm), AEOLISCUS (a genus of fish), OXYURINAE (a sub-family of ducks), VERACIOUS (truthful), and SEYMOURIA (genus of fossil amphibian). [Chris Cole, K. K. S. Bisht, Charles Turner].
Ten-letter words containing the six vowels in any order are ANEUPLOIDY, AUDIOMETRY, BUOYANCIES, AUTOTYPIES, COEQUALITY, EUDAEMONIC, EUKARYOTIC, and OXYURIASES [Philip Bennett, Stuart Kidd, Charles Turner].
The longest word with the five vowels in alphabetical order is PHRAGELLIORHYNCHUS (a protozoan) [Susan Thorpe].
The shortest with the six vowels in alphabetical order is HAREIOUSLY (cruelly), which the OED2 shows in a single citation from a 15th-century manuscript [Susan Thorpe].
Each of the five vowels occurs in both words of the title AMOENITATUM EXOTICARUM, a book written and illustrated by Engelbert Kaempfer and published in 1690 [Charles Turner].
Pierre Abbat says ACEITOU (Portuguese for past tense of to accept) and ALEIJOU (Portuguese for past tense of paralyze) are the shortest words he knows in any language written in the Roman alphabet which have all five vowels in order.
The longest word containing all six vowels, with each vowel occurring only once, is ANTISTREPHORRHYNCHUS (an extinct crustacean) [Susan Thorpe]. Other long words are HYDROMETALLURGISTS and NONUNDERSTANDINGLY [Stuart Kidd]. The longest words containing the six vowels in alphabetical order, each occurring only once, are ABSTENTIOUSLY and MARVEILLOUSLY (variant of marvellously) [Susan Thorpe].
A species of louse, Haemodipsus lyriocephalus, has all the vowels once in each name [Stuart Kidd].
The longest words containing the five vowels in alphabetical order are SUPERCALIFRAGILISTICEXPIALIDOCIOUS (34) and PANCREATICODUODENOSTOMIES (25) [Stuart Kidd].
According to Philip Bennett, the longest words containing the six vowels in alphabetical order are PANCREATICODUODENOSTOMY and PANCREATICODUODENECTOMY (in the Merriam-Webster Medical Dictionary).
The Czech word MATEŘÍDOUŠKY (“thyme plants”) has all six vowels in alphabetical order [Jan Pulkrábek].
ULTRAREVOLUTIONARIES has each vowel exactly twice. The shortest such word is CUBOIDEONAVICULARE (Ligamentum cuboideonaviculare), and the longest, USSOLZEWIECHINOGAMMARUS (a small crustacean) [Susan Thorpe]. PSEUDOPSEUDOHYPOPARATHYROIDISM (which is in OED2) has each vowel at least twice.
OUENOUAOU (a stream in the Philippines) has vowels for 8 of its 9 letters and may be the longest place name with one consonant. PUNAAUIA (a village in Tahiti) has vowels for 6 of its 8 letters [Juozas Rimas]. OUABAIO (an African tree) has vowels for 6 of its 7 letters [Stuart Kidd]. OGOOUE (an African river) has vowels for 5 of its 6 letters.
SUOIDEA (the taxonomic group to which pigs belong) is the shortest word with the five vowels in reverse alphabetical order [Dmitri Borgmann]. The longest such word is PUNCTOSCHMIDTELLA (a crustacean) [Susan Thorpe, Stuart Kidd]. Other words with this property are DUOLITERAL, PRUNOIDEA (a suborder of radiolarian protozoa -OED), JULOIDEA, MUROIDEA (the mice-like rodent family), LEEUWENHOEKIELLA (a marine bacterium), MUSCOIDEA (the family of two-winged flies), PULMONIFERA, RUDOIERA, SUBCONTINENTAL, SUBHYOIDEAN (beneath the hyoid bone), SUBPOPLITEAL, SUBVOICEBAND, QUODLIBETAL (of an issue that is presented for formal disputation), QUODLIBETARY (a quodlibetical argument), TUTOIERA, UNCOMPLIMENTARY, UNCONSIDERABLY, UNCONTINENTAL, UNCONVINCEABLY, UNNOTICEABLY, UNOBLITERABLY, UNOCCIDENTAL, UNORIENTAL, UNPOLICEMANLY, and UNPROPRIETARY [Philip C. Bennett, Charles Turner, Stuart Kidd, Paul Browning].
CWM (a glacial hollow on a hillside) has the rare W as a vowel, as does CRWTH (a type of stringed instrument). Both words are in MWCD10. They are pronounced "koom" and "krooth" (rhyming with room and truth). Other such words, not in MWCD10, are TWP (stupid), AWDL (an ode written in the strict alliterative meters), and LLWCHWR (a city-district in Wales). These words are of Welsh origin. The OED includes numerous archaic spellings in which W or V is a vowel.
The longest word in dictionaries having only one vowel is STRENGTHS.
PSYCHORHYTHMS (W2) is the longest word with only one vowel, ignoring Y [Stuart Kidd].
Some long common German words with only one vowel are SCHRUMPFST (you shrink; 10 letters), SCHRUMPFT (he shrinks; 9 letters), SCHWIMMST (you swim, informal, 9 letters) SCHWIMMT (he/she/it swims 8 letters), STRUMPF (stocking, 7 letters) [Gerd Baron, Robbie Ellis].
Some long words with only one vowel which is allowed to repeat are: MARADANKADAWALAGAMA (a place name in Sri Lanka), KAWAKAWAMALAMALA (a place name in Fiji), TATHAGATAGARBHA, TARAMASALATAS, HANDCRAFTSMAN, ELSENERVELDENVEEN (a place name in the Netherlands), EKHETHEKHETHE (a place name in South Africa), STRENGTHLESSNESSES, DEFENSELESSNESSES, EFFERVESCENCE, RETELEMETERED, DEGENERESCENCE, BEEKEEPER, and perhaps EYELETEERS, which is in OSW but I am unsure whether the Y is a vowel), INSTINCTIVISTIC, LIMLIMTIMIN (a place name in Papua New Guinea), DISINHIBITING, KINNIKINNICKS, PHILISTINISMS, PRIMITIVISTIC, WHIPSTITCHING, MISSISSIPPI, LOXOLOPHODONTS, MONOPHTHONGS, POSTWORKSHOP, OCONOMOWOC (a town in Wisconsin), STRULDBRUGS, CURUCUCUS, DUMBSTRUCK, UNTRUTHFUL, NUMBSKULLS, MUNDUNGUS, USUFRUCT, SUSURRUS, SUCCUBUS, GLYCYLS, RHYTHMS. In addition CHRONONHOTONTHOLOGOS (in Roget's Thesaurus, at "blusterer"), the title and hero of a 1734 burlesque tragedy by Henry Carey, is used for "anyone who delivers an inflated address" (Brewer's Phrase and Fable). In his book Language on Vacation, Dmitri Borgmann calls these words univocalics and lists SYMPHYSY as the longest Y-univocalic [Marc Broering, Dan Tilque, Stuart Kidd, Philip Bennett].
Craig Rowland reports that in Quebec, there is a region known as the Outaouais, which, if in adjectival form, becomes lowercase, hence outaouais. The feminine form of this adjective is OUTAOUAISE, making it an eight-vowelled ten-letter word. He also says that in Quebecois French, the word for bullfrog is OUAOUARON, with six vowels in a row.
OIOUEAE is one of the tropes or Gregorian formulas for the close of the lesser doxology in church music, representing the vowels in "World without end, Amen." [Music Lovers’ Encyclopedia (1954), by Rupert Hughes]
HÄÄYÖAIE, a Finnish word for "a plan for the wedding night," has 7 consecutive vowels, and 6 of the 8 vowel sounds that exist in Finnish [Tapio Tallgren]. However, Juha MÄkinen writes, "There exists another variant of this word body which has 8 consecutive vowels called RIIUYÖAIE. It means 'a plan for the night before a companionship begins...' Both words are very easily understood by a native Finnish speaking person."
In Spanish, REHUÍAOS has all five vowels pronounced, as the "H" is silent. It is a form of the verb rehuir (to avoid) and means "I/he/she/it avoided you" [Ignacio Fernández Galván].
In Hungarian, fiaiéi ("those belonging to his/her sons") has five vowels (and five syllables) and only one consonant [Ádám Szegi].
Gary Rosenberg suggests that QUACKSALVER and QUICKSILVER may be the longest pair of words related by changing two identical vowels to a different set of identical vowels.
OBAMA is the only last name of a President of the U. S. which begins and ends with a vowel.