46 katakana characters, you have a very limited number of sounds to choose from when forming the Japanese equivalent of whatever word you're trying to borrow.
Some stuff translates into katakana just fine. "Coca-cola", for example, becomes "Koka Kora". No problem. But this is not always the case. Since all but one of the katakana characters end with a vowel, each syllable of the word you are creating must also end with a vowel. Additionally, unless the old word ends with an "n", the new word can not end with a hard consonant sound. Therefore, my name "Matt" becomes "Matto".
Also, it should be noted that any sounds beginning with an "L", will start with an "R" in Japanese.
So "la" become "ra", "lou" become "ru", etc. Which means, if you're doing it right, it should sound like you're totally making fun of Japanese people.
I always found it fun to show the "rocals" a picture of my family and then listen to them Japanize the names:
"Here is my dad, Bill."
"And this is my mom, Crystal."
"And here's my brother, Jason."
"And here's my other brother, Ken."
"Ken? That's it? Ken?"
My two favorite borrowed words that didn't make the leap to Japanese so well are allergy (ah-re-ru-gee) and virus (ew-wi-risu). And, sometimes to be mean (and by "mean", I mean "hilarious"), I would write out the sentence "The girl with the wolf is Avirl Lavigne" and have a Japanese person try to read it aloud.
"Za garuru uehzu za urufu izu Abiruru Rabinu."
Anyway, what brought on this little post was that, during this trip, a Japanese friend offered me some Xylitol gum. "Xylitol". As you can see from the picture above, that's what it says on the package.
Now, how do you think this little brand name would be pronounced? Well, based on the first 3 letters of xylophone, I've always pronounced it "zy-li-tol".
Nope. Not even close.
That's not even a word, people.