'X' is pronounced differently at the beginning and in the middle/end of words, why?
Blame the Greeks…
There really is not much reason for the existence of the letter X, as opposed to simply writing “ks”. We only have the letter because the Romans inherited it as part of their alphabet from the Etruscans, who themselves only had the letter in their alphabet because they inherited it from the Greeks.
Early on in the history of the Greek alphabet, there were two ways of writing the “ks” sound. First, there was Ξ, the letter ksi, which is still used in modern Greek for that “ks” sound; second, there was Χ, the letter today known as chi or khi, which is used in modern and most flavours of ancient Greek to write the “kh” sound, but in a handful of varieties of the infant Greek alphabet it was instead used for the “ks” sound.
One of those varieties of Greek which used Χ for that latter purpose were the inhabitants of the Greek island of Euboea, founders of the colony of Cumae on the west coast of southern-middle Italy. The Cumaeans threw their version of the alphabet, funky Χ and all, to the Etruscans, and the rest is a series of unfortunate spellings throughout history.
One such spelling issue happened when Greek words began to be imported into English. English has always had commitment issues when it comes to borrowing spelling from other languages. Most languages, when borrowing a word, will change the spelling and pronunciation to match the conventions of the languages. A handful, such as German, will borrow the word with spelling and pronunciation as close to that of the original language as germanically possible.
English does neither. It’ll borrow the spelling just fine nine times out of ten, like German - but then it alters the pronunciation to fit English conventions. The word “psychology”, for instance, is pronounced as though it should be spelled sicologie, but spelled as though it should be pronounced, well, psychology, more or less as it is in Greek.
That first pair of letters, ps, is represented by a single letter in Greek, Ψ, psi, equally as illogical as X - why not spell it πσ, ps, instead? - but thankfully didn’t find its way on into our modern Latin alphabet. In Greek, starting a word with the “ps” sound is perfectly fine: the word for “psychology” is ψυχολογία, psykhologia, with each letter pronounced.
But English doesn’t like that. English’s phonotactics, its system that says which sounds are allowed to go where in a word, won’t allow “ps” to start a word. You can start a word with “bl”, you can start a word with “dr”, you can start a word with “thr” or “sq”, but you can’t start a word with “ps”. English won’t let you. You can arrange your lips and tongue to say the word, sure, but any word starting with that arrangement of sounds won’t be a proper English word.
So, what do we do when one language with different phonotactics than English hands us one of their words? We keep the spelling, as English does, but we need to fit the word to what English allows sounds to do. With “psychology”, the easiest solution is to knock the “p” off the word, leaving us with “sychology”. We’ve done a similar thing for similar reasons with “tsunami”.
And so too with “xylophone”, and “xenon”, and “xenophobia”, and any and all words beginning with an “x”. English doesn’t like starting words with “ks”, just as it hates word-initial “ps” and “ts”. What does it do to “ks”? The very same it’s done with its phonetic siblings: it plucks out the first “k”, leaving the…well, no, that’s not an “s”, is it? You don’t say “senon”, you say “zenon”. That’s a “z”. Where’d the “z” fly in from?
As it turns out, most likely from English’s phonotactics, too. To be needlessly meta, take the word “example” as, well, an example. You don’t say “eksample”, do you? No, it’s not “eksample”, but “egzample”, where the “ks” sound has shifted over to “gz”. English’s phonotactics tell the “ks” sound that, whenever it shows up in front of a stressed vowel (ex-am-ple, ex-am, ex-ist), to turn into a “gz” sound (egz-am-ple, egz-am, egz-ist).
What happens, then, is this:
- English borrows a word starting with “x” from Greek. Let’s use “xenon”, since it’s short and we’ve been using it well enough so far.
- English looks at “xenon” - pronounced “ksenon” - and says, well, there’s a “ks” sound there in front of a stressed vowel: “xe-non”. We’d better shift that “ks” sound over to a “gz” sound, then.
- And then English notices that “xenon”, now pronounced “gzenon”, starts with a “gz” sound. The “ks” and “gz” sounds are very similar sounds, and as such obey the same rules. English won’t allow words to start with “gz”.
So it does what it did for “ks”, and “ts”, and “ps”: it removes the “g” sound, leaving the “z” behind. - Ergo: zenon.
In the middle (or end) of a word, though? English is fine with having a “ks” or “gz” in the middle (or end) of a word. No problem with that. Phonotactics are happy. So, the pronunciation remains the same, or roughly the same, as it was in Greek when X shows up in the middle (or end) of a word.
Τhis difference exists because English and Greek have different rules for which sounds can go where. When Greek sends a word over to English with sounds in places that would have been fine in Greek but aren’t in English, English has to find a way to deal with them; in this case, it’s by turning “x” into “z” when it comes at the beginning of a word, because English won’t allow “ks” at the beginning of a word, even though Greek will.
