I think some of Tolkien's frustration with his colleague was their various competitions (wagers, if you will) to complete stories, where Tolkien, the niggler never could, while Lewis accomplished in a flash.
As for tengwar, there's a course on-line in the writing - even a character set and a typing aid. There is also a Quenya course and one in Sandarin (although Tolkien never fully finished Sandarin as a language). Tengwar can be applied however to any spoken language. For example, the tengwar on the LOTR book covers is English written in Tengwar, not Elvish tongue(s). There are people who have mastered quenya (sandarin is as difficult as Cherokee - which I do know), the high speech, but although printed out the course and the various dictionaries (how many trees died for that effort, forgive me Fangorn), its slightly less useful than Cherokee (which I only use in my own literature). Tengwar is fun, especially if you use a calligraphy pen. But, of course, I'm a sinologist by degree and have worked with original 12th century Chinese texts. In fact, there's a reverse similarity between the Chinese written character and tengwar. While you can use tengwar to write any language, Chinese characters serve many different languages. The simplified Chinese character now deployed by the People's Republic is fast destroying that basic inherent pan-literate nature of the Chinese languages. Did you ever ask why in a Chinese movie, there are subtitles in Chinese characters? China has 12 separate languages (they're not dialects - but languages), but while Mandarin (kuo-hua - lit. country speech) is spoken by the actors, the written language is shared by all the languages (wen being the written language), so a person in Shang-hai (Wu-hua - Wu speech) may not understand the actor, but they can follow the bouncing ball, so to speak.
Aren't you glad you asked? I will see if I have the links to the tengwar and elvish sites still, and will post them. I am at work, and those links are on my home computer.
Edward C. Patterson