: : We all love Ruth's book. She DID have less material to work
: with, but she got even that wrong. The more you read the book,
: the less you know about Tolkien's languages.

: Languages are something I should eventually know.
: Do you know of any books that accurately cover Tolkien's work?

There is several. Most important is of course getting all of Tolkiens work. Then I recomend you find a site (Forogt site name and URL) made by a very good Tolkien lingust that lists the w´books you ask for. Reading that page will give you better information that I could give here. Someone else might remeber the URL.

: Also, are the transformations of Quenya into Sindarian based on
: anything besides Tolkien's philological mind?
: ................

Quenya did not transform into Sindarin. They are two branches of the same tree, not on different levels on one.