While Tolkien is attributed with writing several languages as part of developing his fictional worlds, the Elvish languages developed for his stories includes basic terminology and are not a languages with large or complex vocabularies.
Tolkien cleverly uses the construct of Bilbo's 'eleventy-first' birthday party bash to transition the tone, from the avucular jokey one he used in The Hobbit, to one more appropriate for the telling of an Epic High Fantasy Quest.
These two languages are the most developed of the Lord of the Rings Elvish languages because material left behind by Tolkien on these two languages is substantial compared to the other Elvish languages found in his writings.
Anne Rice published the first in her vampire series, Interview with the Vampire, in 1976, and at that time there was already a healthy interest in the works of J.R.R. Tolkien in colleges and high schools across the country.
TeacherTube - TeacherTube is a website for teachers and educators all over the United States and around the world offering multiple resources including this section devoted entirely to Tolkien, his works and his languages.