Hi! I'm a community tutor here on iTalki. Many of my students want to learn common American slang, so here are some links to websites that have the best examples of casual language we use. Enjoy! :) Hopefully this is helpful.

https://www.smartling.com/blog/40-american-slang-words-and-phrases-you-need-to-know/

https://www.goodhousekeeping.com/life/g4589/slang-word-meanings/

https://www.fluentu.com/blog/english/american-english-slang-words-esl/