In Aman the speakers of Telerin outnumbered the speakers of Quenya, much as did the Teleri outnumber the Vanyar and Noldor.
From the viewpoint of speakers of Quenya, Telerin was a closely related language still largely intelligible. However, the phonology of the two languages differed much, with Telerin often being more conservative than Quenya.
Finarfin is said to have learned Telerin. He also gave his sons Telerin-influenced Quenya names.