I’m guessing that Speech Pathologists and Linguists develop, over the years, an ear for the odd. By that, I mean we learn to hear quirky things that pass most people by. One of these is the phrase, “But that’s a whole nother thing.” Really? Nother? Is that even a word?
It’s clear that the intent here is to use the words another and whole in a similar way as phrases like “That’s a whole different ballgame” or “That’s another thing altogether,” but somehow the words get mixed up and whole gets wedged into the word another and out pops “a whole nother.”
Because this is an educational site and we hope that folks always leave us feeling that they’ve learned something, there is a name for this phenomenon of slapping a word smack bang into the middle of another; tmesis. You may also like to know that is comes from the Greek τμῆσις meaning “a cutting,” which described how one word is cut into two pieces and a second slotted in.
Tmesis is more typically seen in the realm of profanity. Only last night on the new EsquireTV channel, one of the chefs competing in an edition of the show, “Knife Fight,” said that she was feeling “fan-fucking-tastic” that she’d won. Well, the fucking was bleeped out but you didn’t have to be a skilled lip reader to know what she said. In the UK, something can be “un-bloody-likely” or “abso-bloody-lutely un-fucking-believable.” This insertion of an expletive even has a name; expletive infixation. 
So let’s dig a little deeper here. An infix is a type of affix that appears in the middle of a word, and an affix is a morpheme that can be attached to a word to form a new word. In English, we have prefixes that go before and word, and suffixes that go after. Here are a few examples;
Prefixes: un-, dis-, pre-
unlikely, unbelievable, unhappy, unsure
disable, disappear, disarmed, dishonest
prepaid, prenuptial, prelinguistic, prefix
Suffixes: -ing, -ly, -er
meeting, running, drinking, sleeping
happily, sadly, unhappily, controversially
happier, sadder, reader, editor
Sometimes the prefixes and suffixes may change a little depending on what other letters are around. For example, in- and im- are the same prefix but you chose in- in front of words made with the tongue just behind the teeth (dental) and im- if the word that follows is made with the lips (bilabial).  The same thing happens with the em- and en- prefixes: you empower someone (the letter “p” in power is made with the lips, and you encircle something (the letter “c” in circle is made with the tongue just behind the teeth).
This little foray into tmesis and prefixes leads us back to the “whole nother” issue, and a short trip in an etymological time machine will show us something very interesting about what’s happening here.
Many years ago, in the times of Chaucer, the word another was, in fact, two words; either an + other or – surprise! – a + nother. During the 14th century, the word nother was used as a variant of other and appeared with the article a. In his 1374 work, Anelida and Arcite, Chaucer wrote;
And sawe a noþere ladye proude and nuwe
Notice the split form here – a and nother sitting happily side by side. However, by Shakespeare’s time, the words had fused into another. In Macbeth, Act III, scene I, we see:
And I another
So weary with disasters, tugg’d with fortune,
That I would set my life on any chance,
To mend it, or be rid on ‘t.
He does at times use a split version, but as “an other” and not “a nother.” And by the 18th and 19th centuries, both “an other” and “a nother” appear to have disappeared altogether, with another being the form of choice for writers. Thus, we started with “an other” and “a nother” but changed over a period of a few hundred years to the single word, another.
What we may be seeing now is a re-splitting of the single word brought about the tmetic infixing  of the word whole. And what’s also interesting is that although the word other is used very, very frequently in many situations, the tmesis is between a and nother – a word that doesn’t exist in modern English – and not an and other, which would make some grammatical sense.
But that’s because this splitting doesn’t have to make grammatical sense but phonetic sense; in other words, the choice of where to make the split is not dictated by grammatical accuracy but by phonetic ease. Simply put, it’s easier to say “a whole nother” than “an whole other.”
The word whole starts with a “h” sound, even though it’s written with a “w,” and there’s a rule in English that helps you make the unconscious choice of whether a word is preceded by the article “an” or “a.” If the following word is a consonant, you use “a”; if a vowel, use “an.” So you have “a dog,” “a cat,” “a broom,” and “a spoon,” but in contrast, you have “an egg,” “an ovary,” “an operation,” and “an elephant.” The “h” sound behaves like a consonant so you get “a house,” “a Hobbit,” “a handkerchief,” and “a whole.”  Again, don’t let the “w” fool you – the word is pronounced “hole” (/həʊl/).
So when it comes to wedging whole into another, that unconscious rule pushes you to create “a whole nother” and not “an whole other” because “an whole” breaks the rule. The fact that you might not “know” this rule overtly doesn’t mean that is isn’t there covertly. And the current use of “a whole nother” is further evidence of its existence.
Our discomfort at hearing this phrase is partly brought about because with our grammar hats on, we expect to hear “a whole other”and we balk at the non-word, nother. However, the phenomenon is, as I argued, driven by phonological rules and not syntactic or lexical, and from this perspective, “a whole nother” is oddly correct! This doesn’t mean the Dudes recommend using it – but we do recognize it as a pretty neat linguistic phenomenon.
Join us next time for another fan-bloody-tastic adventure into the world of speech and language!
 For a classic article on this, you should check out McCarthy, J. (1982) Prosodic Structure and Expletive Infixation, Language, 58(3), 574-590, available online via JSTOR at www.jstor.org/stable/413849
 Those of you who are ahead of the curve might say, “But what about words such as ingrowing and ingress which have a “g” after the prefix – why is it in- and not something else?” Well phonetically, it is something else because in both these cases, the actual sound of the “n” turns out to be “ng” – as in “sing” or “bang.” The “n” changes to match the position of the tongue in the sound “g,” which linguists and speechies call “velar.” So for those of you who can read the International Phonetic Alphabet, here are the rules for the in-/im- prefix:
a. “in-” [ɪn] -> [ɪn] /_[+dental]
b. “in-” [ɪn] -> [ɪŋ] /_[+velar]
c. “in-” [ɪn] -> [m] /_[+bilabial]
Give yourself 10 extra smart points if that made sense! And you thought all speechies did was teach people how to say “How now, brown cow!”
 Go ahead. Try slipping “tmetic infixing” into a conversation and see what happens! I guarantee that your Perceived Pretentiousness Score (PPS) will hit an all-time high, and your success at impressing potential romantic partners will hit an all-time low. The Dudes don’t need to worry about this because they already have a high PPS and are married so have no need to impress anyone. My wife just rolls her eyes and suggests I get another drink.
 There are situations where a word is written using the letter “h” but doesn’t actually have the sound of the “h” but a vowel sound. In these cases, the article an is used. So the words hour and honest are written with an “h” but pronounced as “our” and “onest” (/aʊə/ and /ɒnɪst/). Typically, these are words that came from Old French, and French, as we know, is one of those languages where the “h” sound doesn’t appear at the beginning of words.