Why are keyboards not in alphabetical order?  

the keyboard arrangement that we have (QWERTY) was designed based on letter frequency in english so that a typist would be less likely to hit two adjacent keys in quick succession and thus jam the type bars on a mechanical typewriter.

the arrangement was actually designed to slow the typist down (or rather to attempt to make the typing speed more even). of course, when typists came to use computers they required the key arrangement which they are used to.

different arrangements are used for other languages since the letter frequencies are different

i've been wondering about it, too. but i am glad i can type without looking at it. my highschool typing lessons helped a lot. it's so useful for me these days.