Slang is everywhere and changes often
The Spanish language, spoken widely by many different races and cultures, has its own huge assortment of Spanish Slang words and terms. The use of Border Spanish, or Chicano Spanish will show many differences in verbiage and meaning of various words in use.
If you are planning a trip to one of the Spanish speaking countries, you should read a book on Spanish slang, as there is a lot to be learned. Just as slang and idioms in the English language make communication vary greatly from one part of this country to another, so it does with the Spanish language.
The slang terminology changes often so an online dictionary of Spanish slang would me useful reading to keep up with the variations.