How do you pronounce the letter "x" in most spanish words?

Question

How do you pronounce the letter "x" in Spanish?

Answer 1

I copied this from Lazarus' Reference article:

Between vowels or at the end of a word, it sounds like “ks”, as it does in English, although it is normal to relax the pronunciation, and make it sound like “gs”, and in Spain, sometimes like an “s”. This also happens in some English words, like “exam”. At the beginning of a word, it sounds like an “s”.

In medieval Spanish, the “x” was used completely differently: instead of having a “ks” sound, it represented the sound of the modern Spanish “j”, and this can be seen in a few place names, like Mexico, Oaxaca or Texas, that in modern Spanish should have been written as “Méjico”, “Oajaca” and “Tejas”, but since the original spelling is part of their heritage, they keep spelling these with an “x” even though it is pronounced like a Spanish “j”.