One of the world's most intelligent computers was accidentally taught to swear, after researchers showed it the internet.

IBM's Watson computer won fame after winning the gameshow Jeopardy in 2011.

But according to Eric Brown, who built it, the biggest problem with the computer has been making it understand the subtleties of human language.

No, it's personality issues weren't as extreme as other famous computers inspired by IBM's legacy. But it wasn't good.

Particularly bad was Watson's grasp of slang. And as a result, Brown apparently decided to show it the Urban Dictionary - the Internet's prime repository of changing, ambiguous slang.

That was a bad idea.

According to a story in Fortune this month, the result was Watson learned to swear.

It was unable to distinguish between which words were acceptable and which were not, and even used the word "bullshit" in response to a question from a researcher.

The result was that Brown's team had to re-engineer the machine's brain, and delete all references to the Urban Dictionary from its memory banks.

Instead, Brown is now working on turning Watson into a useful diagnostic tool for medical facilities. So it's back on the straight and narrow. Phew.