How are TeX and LaTeX pronnounced?

Knuth called his typesetting program TeX after the word "technology". So the X is actually a capital Greek letter Chi (the same letter as in the beginning of "Xmas"). Those people that can pronnounce this letter correctly should do so. The rest of us just use the lazy approximation in "Tek".

LaTeX was first written by Leslie Lamport, and the "La" comes from his name. There are four different pronunciations of "LaTeX", as follows: "LarTech", "LarTek", "LayTech", and "LayTek". I don't know if any has been made official, so take your pick!