Words…

This sort of stuff fascinates me.
I also have a book called Dubious Doublets that has been on my shelf I have been meaning to get to.

Longest Words
Cabbaged and fabaceae, each eight letters long, are the longest words that can be played on a musical instrument. Seven letter words with this property include acceded, baggage, bedface, cabbage, defaced, and effaced.

Aegilops, eight letters long, is the longest word whose letters are arranged in alphabetical order. Seven letter words with this property include beefily and billowy. Six letter words include abhors, accent, access, almost, biopsy, bijoux, billow, chintz, effort, and ghosty.

Spoonfeed, nine letters long, is the longest word whose letters are arranged in reverse alphabetical order. Trollied is an eight letter word with this property. Seven letter words with this property include sponged and wronged.

Cimicic and Cimicid, each seven letters long, are the longest words that are exclusively made up of Roman Numerals.

Nonsupports, eleven letters long, is the longest word in the English language made up of only letters in the second half of the alphabet. Ten letter words include prosupport, soupspoons, and zoosporous.

Overnumerousnesses, eighteen letters long, is the longest English word that consists of only letters that lack ascenders, descenders, and dots in lower case. Overnervousnesses is seventeen letters. Sixteen letter words with this property include curvaceousnesses and overnumerousness. Fifteen letter words with this property include erroneousnesses, nonconcurrences, overnervousness, and verrucosenesses.

Lighttight and lillypilly, each ten letters long, are the longest English words consisting only of letters with ascenders, descenders, or dots in lower case.

Tittifill, nine letters long, is the longest English word consisting only of letters with ascenders or dots in lower case. Eight letter words with this property include libidibi and tikitiki.

The only English words that consist entirely of letters with descenders in lower case are gyp and gyppy.

Honorificabilitudinitatibus, 27 letters long, is the longest English word consisting strictly of alterating consonants and vowels. An eighteen letter word with this property is epicoracohumeraler. A seventeen letter word with this property is hypovitaminosises. Sixteen letter words with this property include aluminosilicates, depolarizability, and supererogatorily. Fifteen letter words with this property include cytomegalovirus, heterozygosises, hexosaminidases, paramyxoviruses, pararosanilines, parasitological, tenosynovitides, tenosynovitises, unimaginatively, and verisimilitudes.

The Rot13 method of encrypting text is performed by rotating the alphabet by thirteen characters. Because there are 26 letters in the alphabet, the decryption process is the same as the encryption. The longest words to form other words when Rot13 encrypted are the seven letter words abjurer and nowhere, which become each other.

Letters
Dermatoglyphics, misconjugatedly, and uncopyrightable, each fifteen letters long, are the longest English words in which no letter appears more than once. Fourteen letter words with this property are ambidextrously, benzhydroxamic, hydromagnetics, hydropneumatic, pseudomythical, schizotrypanum, sulphogermanic, troublemakings, undiscoverably, and vesiculography.

Esophagographers and unprosperousness, each sixteen letters long, are the longest English words in which each of their letters occurs at least twice.

Esophagographers, sixteen letters long, is the longest English word in which each of its letters occurs exactly twice. A fourteen word with this property is scintillescent. Twelve letter words with this property include happenchance and shanghaiings. Ten letter words with this property include arraigning, concisions, intestines, and horseshoer.

Sestettes is a word in which each of its letters occurs three times.

The word chincherinchee is the only known English word which has one letter occurring once, two letters occurring twice, and three letters occurring three times.

Ultrarevolutionaries is a word in which each of the five main vowels occurs twice.

Eunoia, six letters long, is the shortest word in the English language that contains all five main vowels. Seven letter words with this property include adoulie, douleia, eucosia, eulogia, eunomia, eutopia, miaoued, moineau, sequoia, and suoidea. (The scientific name iouea is a genus of Cretaceous fossil sponges.)

Caesious, eight letters long, is the shortest word in the English language that contains all five main vowels in alphabetical order. Nine letter words with this property are acheilous, acheirous, aerobious, arsenious, arterious, autecious, facetious, and parecious.

Suoidea, seven letters long, is the shortest word in the English language that contains all five main vowels in reverse alphabetical order. Other words with this property are scarce; they include the ten letter words duoliteral and unoriental, the fourteen letter word subcontinental, and the fifteen letter words neuroepithelial and uncomplimentary.

Facetiously, eleven letters long, is the shortest word in the English language that contains all six vowels in alphabetical order. A twelve letter word with this property is abstemiously. The fourteen letter words adventitiously and sacrilegiously have this property but also have repeated vowels.

Twyndyllyngs, twelve letters long, is the longest word in the English language without any of the five main vowels. An eleven letter word with this property is the singular form, twyndyllyng. An eight letter word with this property is symphysy. Seven letter words with this property include gypsyfy, gypsyry, nymphly, and rhythms.

Strengths, nine letters long, is the longest word in the English language with only one vowel.

Strengthlessnesses, eighteen letters long, is the longest word in the English language with only one vowel repeated. A seventeen letter word with this property is defenselessnesses. A sixteen letter word with this property is strengthlessness. A fifteen letter word with this property is defenselessness. A fourteen letter word with this property is degenerescence. Thirteen letter words with this property are degenerescent, disinhibiting, effervescence, handcraftsman, kinnikinnicks, philistinisms, primitivistic, retelemetered, and whipstitching.

Euouae, six letters long, is the longest English word consisting only of vowels, and, also, the English word with the most consecutive vowels. Words with five consecutive vowels include cooeeing and queueing.

Archchronicler, catchphrase, eschscholtzia, latchstring, lengthsman, and postphthisic each have six consonants in a row. Borschts has six consonants in a row in just one syllable. Words with five consecutive consonants include angstrom, angsts, birthplace, dumbstruck, eighths, heartthrob, lengths, postscript, strengths, thumbscrew, twelfths, warmths, and witchcraft.

Hotshots consists of the same four letters repeated. There are other eight letter words with this property, but none are common: beriberi, caracara, chowchow, couscous, froufrou, greegree, guitguit, kavakava, lavalava, mahimahi, and matamata.

Abcaree, abchalazal, abcoulomb, crabcake, and drabcloth are among the only words in the English language that contain “abc.”

Hydroxyzine is the only word in the English language that contains “xyz.”

The longest alphabetic sequences to appear in English words are “mnop” and “rstu.” Mnop appears in such words as gymnopaedic, gymnophiona, gymnoplast, limnophilous, prumnopitys, semnopithecus, somnopathy, and thamnophile. Rstu appears in such words as overstudy, overstuff, superstud, and understudy.

You and ewe are pronounced the same but share no letters in common. Eye and I is another such pair. Oh and eau is yet another.

Subbookkeeper is the only English word with four pairs of double letters in a row. Assessee and keelless are the shortest words with three pairs of double letters. Cooee is the shortest word with two double letters.

Only a few words (not counting three letter words) start with the same three letters they end with. They include: aftershaft, anticipant, anticoagulant, anticonvulsant, antiformant, antioxidant, antiperspirant, calendrical, entablement, entanglement, entertainment, enthrallment, enthralment, entrapment, hotshot, ingesting, ingratiating, ingrowing, ionization, microsomic, nicotinic, physiography, phytogeography, phytography, redeclared, respires, restores, restructures, tormentor, and underground. As a special case, six letter words with this property are atlatl, bonbon, booboo, bulbul, cancan, chichi, dumdum, grigri, motmot, murmur, pawpaw, pompom, tartar, testes, and tsetse.

Fewer words (excluding four letter words) start with the same four letters they end with. These include uricosuric and the nonsense word abracadabra. As a special case, eight letter words with this property are beriberi, caracara, chowchow, couscous, froufrou, greegree, guitguit, hotshots, kavakava, lavalava, mahimahi, and matamata.

Typewriters
Aftercataracts and tesseradecades, each fourteen letters long, are the longest words that can be typed using only those letters normally typed with the left hand. Twelve letter words with this property include aftereffects, desegregated, desegregates, reasseverate, reverberated, reverberates, and stewardesses.

Johnny-jump-up and niminy-piminy, twelve letters long, are the longest words that can be typed using only those letters normally typed with the right hand. Eleven letter words with this property include hypolimnion and kinnikinnik. Nine letter words with this property include homophony, homophyly, monophony, nipponium, nonillion, pollinium, and polyonomy.

Leptothricosis and leucocytozoans, each fourteen letters long, are the longest English words that are normally typed using strictly alternating hands. Thirteen letter words with this property include antiendowment, antisudorific, autotoxicosis, dismantlement, leucocytozoan, and neurotoxicity. Twelve letter words with this property include authenticity and suspensorial.

Postmuscular, twelve letters long, is the longest English word that is normally typed by switching hands every two letters.

Rupturewort, eleven letters long, is the longest word that can be typed using only those letters in the top row of a typewriter. Ten letter words with this property are pepperroot, pepperwort, pewterwort, pirouetter, prerequire, pretorture, proprietor, repertoire, repetitory, tetterwort, and typewriter.

Shakalshas, ten letters long, is the longest English word that can be typed using only those letters in the middle row of a typewriter. Nine letter words with this property include flagfalls, hadassahs, and haggadahs. Eight letter words with this property include alfalfas, galagala, galahads, and haskalah.

Deeded, hummum, muhuhu, and muumuu, each six letters long, are the longest English words that are normally typed with just one finger. Five letter words with this property include ceded, mummy, unnun, and yummy.

Symmetry
CHECKBOOK, nine letters long, is the longest word in the English language composed entirely of letters with horizontal symmetry in upper case. Eight letter words with this property include BEDECKED, BOOHOOED, CODEBOOK, COOKBOOK, DOBCHICK, EXCEEDED, HOODOOED, and KEBOBBED.

HOMOTAXIA, nine letters long, is the longest word in the English language composed entirely of letters with vertical symmetry in upper case. Eight letter words with this property include AUTOMATA, AUTOTOMY, MOTIVITY, MAHIMAHI, MATAMATA, MYXOMATA, and THATAWAY. Seven letter words with this property include AUTOMAT, MAMMOTH, MAXIMUM, TAXIWAY, WITHOUT, and the proper name TIMOTHY. Hyphenated terms with this property include HOITY-TOITY and MOUTH-TO-MOUTH.

HAH, HOH, HUH, MA’AM, MOM, OHO, TAT, TIT, TOT, TOOT, TUT, and WOW are several words which, when written in upper case letters, have vertical symmetry.

I, OHO, and IHI’IHI are the only words in the English language that, when written in upper case letters, have horizontal and vertical symmetry and consist entirely of letters that have both horizontal and vertical symmetry.

ZOONOSIS, eight letters long, is the longest word in the English language composed of letters with 180 degree rotational symmetry. Six letter words with this property include NINONS, ONIONS, and SOZINS.

MOW, SIS, and SWIMS, when written in upper case letters, have 180 degree rotational symmetry.

COUSCOUS, eight letters long, is the longest word in the English language such that one cannot tell visually if it’s been written in all upper case or all lower case letters. Four letter words with this property are COCO, COOS, COWS, CUSS, SCOW, VOWS, WOOS, WUSS, and ZOOS.

Anagrams
Conservationalists and conversationalists, each eighteen letters long, are the longest non-scientific English words that are anagrams of each other. Internationalism and interlaminations are sixteen letter anagrams of each other.

Basiparachromatin and marsipobranchiata, each seventeen letters long, are anagrams of each other that have no more than three consecutive letters in common. Thermonastically and hematocrystallin are sixteen letter anagrams of each other that have this same property.

Nitromagnesite and regimentations, each fourteen letters long, are anagrams of each other without any consecutive letters in common.

Interrogatives, reinvestigator, and tergiversation, each fourteen letters long, are the longest three non-scientific English words that are anagrams of each other. They have no more than three consecutive letters in common with each other.

Monday is the only day of the week that has an anagram, which is dynamo. March, April, and May are the only months of the year that have anagrams, which are charm, ripal, and yam.

Earth, having the anagrams hater and heart, and Mars, having the anagrams arms and rams, are the only planets with anagrams.

Contained Words
Thitherwards contains the most English words spelled consecutively within it: a, ar, ard, ards, er, he, her, hi, hit, hithe, hither, hitherward, hitherwards, I, it, ither, the, thither, thitherward, wa, war, ward, and wards, totaling twenty-three words. Therein, seven letters long, contains twelve words: er, ere, he, her, here, herein, I, in, re, rein, the, and there.

Ushers contains the most personal pronouns spelled consecutively within it: he, her, hers, she, and us, totaling five pronouns.

Syllables
Scraunched and the archaic word strengthed, each ten letters long, are the longest English words that are only one syllable long. Nine letter monosyllabic words are scratched, screeched, scrounged, squelched, straights, and strengths.

Rugged is a two syllable word that can be made one syllable by adding letters to it to make shrugged. The two syllable word ague can be made one syllable by adding letters to make it vague or plague.

Are is a one syllable word that can be made into a three syllable word by adding just one letter to make area. Similarly, came can become cameo, gape can become agape, and lien can become alien. Adding a letter to the middle of smile becomes the three syllable word simile. Similarly, whine can become wahine.

Io may be the shortest two syllable word in the English language. Other candidates are aa, ai, and eo, but there is some dispute over the pronunciation and legitimacy of these words.

Iouea, five letters long, is the shortest four syllable English word. Oceania, oogonia, and oxyopia, each seven letters long, are the shortest five syllable English words.

Chasm, dirndl, massacring, rhythm, sarcasm, and vrbaite have more syllables than pronounced vowels. Contractions and words that end in ism and ithm also have this property. Proper names with this property include Edinburgh and Hamtramck.

Articles
Sometimes redundancy creeps into accepted usage when terms are translated from one language to another. Rio Grande River is redundant to a speaker of both English and Spanish, as is Sierra Mountains, but, when addressing an English speaker, the extra English specification makes sense.