affectation

/ˌa-ˌfek-ˈtā-shən/

borrowed from Middle French & Latin; Middle French affectation, borrowed from Latin affectātiōn-, affectātiō "striving after, strained manner (in rhetoric)," from affectāre "to strive after, try to accomplish, pretend to have" + -tiōn-, -tiō, suffix of action nouns

noun

  1. speech or conduct not natural to oneself : an unnatural form of behavior meant especially to impress others

  2. the act of taking on or displaying an attitude or mode of behavior not natural to oneself or not genuinely felt

  3. a striving after

His French accent is just an affectation.

speaking honestly without affectation

pose air airs affectation mannerism mean an adopted way of speaking or behaving. pose implies an attitude deliberately assumed in order to impress others. air may suggest natural acquirement through environment or way of life.