In Japanese, using Katakana, why is the name Danny written and pronounced ダニー. Why not just ダニ? I'm not sure why the
i is being extended when this doesn't really happen in english.
To build on koji's answer, sometimes you'll see changes in the katakana-ization of foreign words and names to avoid collisions with native words and names. An additional incentive for the long "y" sound is that there's a native word だに, which means "mite or louse" (that is, a small blood-sucking arthropod). It's probably a *good* thing that the katakana pronunciation of "Danny" has shifted the way it has. :)
I believe it's simply the way the word was borrowed. Each English or other loanword in Japanese has or eventually acquires a standard writing. Of course some have more than one accepted writing, but the point is the transliteration can seem arbitrary or like it's more different from the original language's pronunciation than it is. Indeed, in some cases it probably is somewhat arbitrary, the way Japanese speakers end up adopting English, German, Portuguese or other languages' words. But I doubt anyone knows for sure, including native Japanese speakers. xP I don't know, that is for sure.
However, I probably can answer adequately in the case of the word you specifically asked about. To answer this question about Japanese, however, I'll have to let you in on a little secret about English pronunciation.
First of all, ダニー isn't necessarily one of those words that have a random or arbitrarily assigned pronunciation in Japanese that is different from English. Believe it or not, phonetically at least, English actually does feature short and long vowels, like the "ii" in "Danii"; although unlike Japanese, vowel length is not phonemic (i.e., it's only phonetic), but that's not important.
What this means basically is that while most English speakers (apart from English linguists and similar groups) don't even realize it, or make a big deal out of it, vowel length does exist in English. For example, try this:
- Say "bad" the way you normally do.
- Now say "bat" your usual way.
Listen carefully to the vowel 'a' in each word. If you're like most native English speakers, you'll notice the 'a' in "bad" is held slightly longer than that in "bat". This is because in most varieties and dialects of the spoken English language, the length the vowel/diphthong in a stressed syllable is related to whether the consonant or consonant cluster that follows it is voiced or voiceless. Stated more simply, in English, for single-syllable words, a pre-consonantal short vowel in a stressed syllable is generally lengthened before a voiced consonant. Of course, that's a great over-simplification of the English vowel length system, but you get the point.
Actually, even consonants can be doubled in English, the way they are in Japanese. This is most clearly evident in the standard American English pronunciation of "thirteen", for instance, where most speakers say what sounds like "thurt" + "teen" instead of the usual British "thuh" + "teen".
Now, this is where your question comes into play. And that's because, in English, many word-final vowels are spoken long, as well. And native Japanese speakers, being conditioned to hear the difference between short and long vowels more explicitly than English speakers, are able to pick up on the fact that the word-final 'y' at the end of "Danny" is pronounced long by most English speakers. Keep in mind, of course, that English long vowels aren't quite as long as Japanese usually, except in certain dialects, like the "Southern drawl" of the United States, but even standard American English features phonetic vowel length, even though it's not taught in school because it generally doesn't affect/create any minimal pairs (i.e., words that differ only in vowel length).
So finally, we have an answer:
"Danny", or "ダニー" in Japanese, was transliterated with a long vowel because there is a long vowel in the English pronunciation, for most native speakers. I'm sorry for the long, possibly tedious answer, but it's the most concise I can explain it without using purely linguistic jargon, and that would be inexcusable hehe. =) If you want more information on English vowel length, there's plenty available on Wikipedia, as well as many other sites, I'm sure.