Grammar
Different people speak with grammar that differs from that of other people.  For example, people who use the dialects called General American English and BBC English might say, I didn't do anything, while someone who speaks what is called African American Vernacular English or AAVE might say, I didn't do nothing. London working class version: I ain't done nuffink!  These are called double negatives, and are found almost entirely in spoken English, and seldom written.