It’s about stuttering, and the MPAA rated it R for profanity - specifically, for the guy spouting f-bombs for therapy. (Seriously: that was apparently a true part of the story.) So, keep those ‘positive reviews’ in perspective:
Lionel Logue (Rush) is a speech teacher with unorthodox methods. He insists on a first-name intimacy with his patients, instructs them to sing “Swanee River” and use vigorous profanity, [emphasis added] probes their childhoods for the trigger to their infirmity.
Source: time.com/time/arts/article/0,8599,2017645,00.html
DISCLAIMER: Catholic Answers has turned over the archive to Catholic-Questions.org and no longer owns, manages, or moderates the forums. For additional apologetics resources please visit www.catholic.com.