The evidence of Charles Jones, an English language specialist at the University of Edinburgh, secured justice last week for Glaswegian Kenneth Kinnaird.
Mr Kinnaird was convicted of resisting arrest after he told police to "**** off" when asked to wait while they checked if a warrant was out for him.
His conviction was quashed after Professor Jones told the Edinburgh Appeals Court that people often did not mean offence when they swore. "You swear and I swear, especially when I am on the golf course, but we are not insulting anyone."