For the longest time, this caused a lot of amusing controversy and speculation.
After the original recording was changed, they could finally reveal the secret and did so, during a Chat Session. (slightly incorrect though)
In Season 6, Kenny's verse was replaced by one from Timmy. In Season 7, Kenny returned with another new verse.
Seasons 8, 9 & 10 have been using this verse too and The Studios has not "officially" revealed the translation. (but have unofficially)
Season 10.5 started Oct. 4, 2006 and they have changed Kenny's verse, once again.

For a little while there was a posting on Wikipedia's Kenny page that a South Park Editor revealed all of Kenny's Theme Song lines.
That was in October 2007 and though it seemed legit there were no sources listed and the whole section has since been removed.
So, I decided to put this page back to what I originally intended it to be...

SEASONS 1 & 2

Kenny's translation was officially revealed by Matt & Trey during a Yahoo! Chat session on June 28, 1999.
This translation is also posted at South Park Studios FAQ - Sept. 2001.

"I like girls with big fat titties, I like girls with deep vaginas."

LISTEN FOR YOURSELF ~ My Way

SEASONS 3, 4 & 5

Matt & Trey revealed this translation during the same Yahoo! Chat session above & is also posted at SPS FAQ.

"I have got a ten inch penis. Use your mouth if you want to clean it."

SEASON 7.0

This translation came from the mysterious South Park Editor posted at Wikipedia and later removed.
It does appear to be correct although there is no "official" word that this it is.

"Took a while, but hear me talking, suck my dick and suck it fast."

LISTEN FOR YOURSELF ~ Hyper Speed

SEASONS 7.5, 8, 9 & 10.0

South Park Studios did post this translation but said Matt couldn't recall exact wording so it is close enough.

"Someday I'll be old enough to stick my dick in Britney's butt."

SEASONS 10.5, 11 & 12

The second half of Season 10 had a new verse for Kenny and is currently the one they are using.

LISTEN FOR YOURSELF ~ Regular ~ My Way ~ Hyper Speed

After listening a few more times, I am pretty sure this is the translation but still no "official" word.
"I like fucking silly bitches. I know that my penis likes it."

Here are some other translations sent in by you Fans...

Me - 7.29.07 = "Girls like fucking, you like fucking. I know my penis likes it."
CrazyRach - 7.29.07 = "I like fucking, tittie sucking. I want girls who wanna suck it."
sp4lfe - 7.15.07 = "I like fucking, cigar puffing. You don't like it, go and suck dick."
Jonny (London) - 7.17.07 = "We all like fucking do you like fucking wanna go fucking my penis likes it."
Brian S. (Wash.DC) - 7.17.07 = "I like fucking, you like fucking, we like fucking penis fucking."
Simon W. (Scotland) - 8.29.07 = "I like fucking, titty sucking, how about some titty fucking?"
Random Dude - 9.21.07 = "Girls like to suck my dick, you like to suck my dick."
roe-ur-boat (Ireland) - 10.4.07 = "I like fucking, you like fucking, We all like to penis fucking."
NIGathan (Texas) - 10.11.07 = "I said I'm Kenny fuckin Kenny fuckin Kenny fuckin."
andertly5678933 - 10.15.07 = "I like fucking you like fucking we all like penis fucking."
Aaron (New York) - 10.16.07 = "I like fucking titie sucking and I know my penis likes it."
D.R.N. (L.I) - 12.21.07 = "I like hearing stinky bitches, use your hand if you wanna touch it"
Milo (South Africa) - 3.5.08 = "For a change I'm singing nicely. Please stop fucking killing Kenny."
 " " " = "Kenny likes wet hot pussy. Cartman's mom just won't do it."
Chris (Hawaii) - 3.7.08 = "I like fucking silly bitches. I really love fucking silly bitches."
CC - 3.8.08 = "I love fucking, she loves fucking, I love it when she sucks my dick."
Chris Penga (Texas) - 3.8.08 = "I like fucking silly bitches, I don't think my parents like it."
hitman540 - 3.24.08 = "I like fucking silly bitches, I won't vote for Hillary Clinton."
Travis (BC) - 3.26.08 = "I like fucking silly bitches, you won't vote for Hillary Clinton."
 " " " = "I won't vote for Hillary Clinton, you won't vote for Hilary Clinton."
 " " " = "I like fucking silly bitches. You like fucking silly bitches."
    [ hmm, BC is Canada, eh? then it is ok you send in 3, I still clearly hear, 'penis likes it' as the ending words -Me ]
kenneth kenny mckormick (south park colorado) - 3.31.08 "I like fucking silly bitches, I know that my penis likes it!"
Veras Marrero - 4.10.08 "I like fucking silly bitches, I know that my penis digs it."
GoF (Sboro, GA) - 4.26.08 "I like fucking silly bitches, I like fucking Paris Hilton."

Can you understand what Kenny is singing? Send in your translation via the BRICK WALL -->>>

THEME TRIVIA

The first 13 episodes [Season 1] had the same music during ending credits, except for one.

Big Gay Al's Big Gay Boat Ride
The music had lyrics of, " I'M A MAN ".
[ by DVDA - Trey & Matt's band ]

Seasons 2, 3, 4 & 5 endings have all been different.
Sometimes they play a song that played during that same episode at the end and sometimes the guitar ditty.

Have you seen the Kenny Portal?

~ Kickass! Shop of South Park ~
~ Dead Kenny Jacket ~ "Oh My God They Killed Kenny" T-Shirt ~ Kenny Patch