Although I haven’t purchased it, I saw a book on Neo- Sindarin, which basically took all of the roots from Sindarin in the books, and made it more linguistically friendly/ structured.

As far as websites go, I’m not sure 🤔

I don't know of any sites or books but I agree that it would be amazing to be able to speak Elvish. Imagine having that as a talent.

Elfdict.com is very good, and it has all the languages