what is the diffrence between using words "say", "tell" and "speak"???Explain it to me please

Question

Answer

This is quite easy to look up. I've even found pages with a bonus: talk.

http://staff.washington.edu/marynell/grammar/tellsay.html

See how you go with these exercises:
http://speakspeak.com/english-grammar-exercises/intermediate/tell-say-speak-talk-differences

Answer

you can speak a language (an ability or a choice)
you can tell a story or something
but you can say something