The head researcher at IBM had an idea of training Watson to understand natural language as he believed that ability to understand slangs would probably be an ultimate test that would ensure that Watson could understand the way real people communicate. To put this into practice Watson was made to learn the Urban Dictionary.
There was a slight problem though as the dictionary was made up of swear words along with nasty and dirty words which the Watson learned as well. The end result “Watson couldn't distinguish between polite language and profanity -- which the Urban Dictionary is full of”, revealed Brown in an interview with Fortune Magazine.
“Watson picked up some bad habits from reading Wikipedia as well. In tests it even used the word "bullshit" in an answer to a researcher's query”, he added.
To stop Watson from using the cuss words, Brown not only had to develop a filter that would stop the supercomputer from swearing but also had to scrape the entire Urban Dictionary from the computer’s memory.