i've a general question for you guys:

i don't get the whole "big picture" as far as latin and greek go. it seems so many of our words' etymologies suggest something along the lines of "from Latin xxxx from Greek yyyy"... so which came first? did they coexist? did one derive from the other? or did they each bother from the other? how different is the Greek language today from that of ancient times?

someone enlighten me, pretty please =)