Why? Because having been yanked from a culture-specific collective consciousness and being transplanted into another, I realized that some words in patois simply have no English equivalent, and it takes forever to explain them to others. Therefore, a huge portion of my lexicon was rendered useless, lest I use these Jamaican words and make an ass of myself.
Here's a fun list of a few words that have special 'culture barriers' built in for maximum embarassment:
To North Americans, this word usually means 'crazy' or 'mentally unstable'. To Jamaicans, it means 'butt' or 'ass' - hence the lulzfest that ensued when I first watched Ferngully and heard the bat sing this song.
If you think that this word simply means 'friend' you'd be correct - unless, of course, you're Jamaican and you are brought up to think that this means 'penis'. Fun times are sure to ensue when on a field trip to your local art museum and your teacher says to you, a female student, "Giselle, where's your buddy? We're using the buddy system today." (Not only do you get inappropriate laughter met with confused looks, but you also get a little bit of gender confusion. Two for one deal - HURRAH!)
Jamaicans say 'hush' as a means of soothing someone or wishing them a speedy recovery from whatever is ailing them. Everyone else in the world says 'hush' as a polite way of telling them to stfu. An excerpt from a conversation in the 8th grade:
Brand New Friend: "I feel horrible - I have the worst cramps!"
Giselle: "Awww hush!"
Brand New Friend: "....asshole."