I don’t speak elvish fluently or anything, but maybe this could help -

http://www.angelfire.com/empire2/angora5/Translator.html

It might be useful if we knew what the phrase you’re trying to translate is.

Since “snuggie” is such a new word to even our language, there probably won’t be a translator that will recognize it- much less have an elvish equivalent for it. Try replacing that with another word and then resub it in afterwards?

I’ve had similar issues with Elvish translators and learning Elvish (because that’s something I’ve tried to do.) Eventually I just settled for learning the alphabet and then writing words in English, but in Elvish script. You could just do that? I mean, I know it’s not the same, but it’s something.

Actually, most of what we have from Tolkien in “elvish” is actually just english transliterated into his sindarin characters — so there’s certainly precedent for the “just write it in the characters.”

Now for the phrase “you can’t go adventuring in a snuggie” Obviously as Ada Rose pointed out “snuggie” is not gonna happen. Closest I could find was “Haust” for bed and “Tog” for bring. There’s a pretty strong precedent to create compound words through simple elision, so “Haustog” or the like may be a good choice for “the bed that you bring” ie. a sleeping bag, bed roll or snuggie. (the idea “bed with sleeves” is a good one, but we don’t have a word for sleeves either.)

Adventure is likewise hard to get, but we can get a decent translation into Journey which is “Lend” (this is the word from which the famous “Lembas” is created, “Lend” for journey + “Bass” for bread gets us “Lembas”). It seems likely then that the elven word that would have been used to describe Frodo’s quest to destroy the ring was likely “Lend”.

The english preposition “in” is actually indicating possession and use instead of relative position, so we would be better served by translating the preposition “with”. At least there’s a straight translation there: “Na” But that doesn’t really capture the idea of trying to fight orcs while garbed in a blanket with sleeves, so I think we would be better served looking for the gerund form of the verb to clothe which is “hebi” for a gerund of “hebed”

The personal article “you” is “chín” and the imperative voice of the verb of potential and capability is “garo” the negative denoted by the prefix “ú-”

So the translation should be. ” chín ugaro herio i lend hebed na i haustog.” or ” You can’t begin a journey clothed in a bedroll.”

I went ahead and made an image for you of the sindarin characters (I don’t think you can embed images here) but you can visit it on my picasa album