"it is not a complete language"
I did not know there
was such a thing?!
As to wether any further strivings toward completeness will ever be generally accepted by mainstream speakers of Quenya that is another question, but with the publication of many, many fragments, poems, prayers, etymologies, etc in the
Vinyar Tengwar Journal and JRRT's old but still relevant Qenyaqesta Lexicon in Parma Eldalamberon 12 [dig around onabove link and you will find it], our number of stems and roots and words [in Quenya or proto-Quenya, and thus often usable] has grown greatly.
btw, if some [like myself] find Helge's course a wee bit much to start off with, the following has been provisionally recommended:
Nancy Martsch's Basic Quenya
I hope to order a copy soon myself.