Which are your first language rules if you have more than one language.
As people are from different diversity makes also languages to be different across the world. some times because of circumstances one is supposed to know more languages in order to fit properly in the modern society, otherwise if you don't teach yourself some languages you might not understand what is happening around the globe. Every language has it's rules that when using it you must observe in order to pass information correctly to those people who know that language. sometimes especially when people are using their second language tend to make some funny mistakes which reduce the clarity of the message he /she wanted to pass. How do you take it when you see somebody violating the rules of the language that is best known to you? Are you suppose to teach that person?