I just… can’t. It’s lay-teks to me. I have to deal with non-technical people and having every conversation about a LaTeX feature turn into a “well, actually” discussion of Ancient Greek sounds like hell for all of us.
Well, first of all LaTeX is derived from TeX. And the X isn't an x but the Greek letter X whose pronunciation seems to depend on Greek epoch and also geographic preferences. The final say would have Donald Knuth. I think he said it's like the Ch in (Happy) Chanukka ...
And again, a case where the creator could have done everyone a favor and not given it an obscure name that only an academic (and probably not many of those) would be able to pronounce correctly.
That’s one controversy that shouldn’t be. Quoth Knuth (The TeXbook, chapter 1, “The name of the game”):
> Insiders pronounce the χ of TeX as a Greek chi, not as an ‘x’, so that TeX rhymes with the word blecchhh. It’s the ‘ch’ sound in Scottish words like loch or German words like ach; it’s a Spanish ‘j’ and a Russian ‘kh’. When you say it correctly to your computer, the terminal may become slightly moist.