Teens may see more actors kicking the crap out of each other in movies this summer, but they'll hear half as many swear words than they would have 25 years ago at the theater.

Trends are showing that movies directed at teenagers, though more violent, thrust fewer dirty words in their direction, according to a study by three BYU communications professors. The trio analyzed 90 top-grossing movies from 1980 to 2006, coding a myriad of words — from the Federal Communication Commission's "seven dirty words" to sexual, excretory, mild and strong words — and found that today's movies contain half the bad language.

"We were quite surprised at the findings," said Mark Callister, one of the authors of the study. "When you consider that profanity is increasing on television, especially during the 9 to 10 p.m. hour, and in music lyrics, you often expect to find similar trends in other media."

Box office performance was used because it suggests the movie's popularity and indicates the strength of the film's distribution outside theaters, such as home rentals and downloads. The genre of teen films was selected based on whether the story line centered on teens and the film featured actors ages 12 to 17 and teens in major and minor roles. Only G-, PG- and PG-13-rated films were included because teens aren't supposed to see R-rated movies without a parent or guardian.

In the 90 films surveyed, there were 2,311 instances of profanity.

The 1980s movies, including "Back to the Future," "Honey I Shrunk the Kids" and "Karate Kid," averaged 35 instances of profanity per film, while that figure dropped to 25 profanities in the 1990s in movies like "Clueless," "The Brady Bunch Movie" and "Little Big League," and dropped again to 16 instances per show in the 2000s in movies including "Spider Man", "Harry Potter" and "Remember the Titans."

Most commonly used profanities are classified as mild words, including "damn" and "hell," and they constitute 57 percent of the coded bad words.

The FCC's dirty seven — words not suitable for public broadcast or print in a family newspaper — showed up 508 times in the movies or 22 percent, while strong, sexual and excretory words accounted for 21 percent.

According to the report, published in the May issue of the Journal of Children and Media, teens in movies are more likely to use the seven dirty words prohibited from television than adults. Adult characters and typically females use mild words whereas males use more foul language