A teacher’s role may be to expand a student’s vocabulary, but one Arizona lawmaker wants to make sure that doesn’t include four-letter words, the Associated Press reports. A state legislator has introduced a bill that would punish public school teachers if they use words that violate the obscenity and profanity guidelines set forth by the Federal Communications Commission. State Sen. Lori Klein introduced the measure because a parent in her district complained about a high school teacher using foul language…