Quenya

Quenya was one of the languages spoken by the Elves. It was the tongue that developed among those non-Telerin Elves who reached Aman (the High Elves) from an earlier language called Common Eldarin. Quenya was typically written with the Tengwar of Fëanor. An older script, Rúmil's Sarati, was used also. Of the three clans of Elves in Aman, the Noldor and the Vanyar spoke slightly different, though mutually intelligible, dialects of Quenya (Valinorean Quenya and Vanyarin Quenya respectively). Following the Exile of the Noldor in the First Age, a third dialect, Exilic Quenya or Noldorin Quenya, developed among the Noldor who had journeyed to Middle-earth. In general practice, the word Quenya usually refers to Noldorin Quenya, since it was the only Quenya dialect spoken in Middle-earth.
The language was also adopted by the Valar who made some new introductions into it from their own language, though these loanwords are more numerous in the Vanyarin dialect than the Noldorin one. This is probably the case because of the enduringly close relationship the Vanyar had with the Valar. The third clan in Aman, the Teleri, spoke a different, closely related language: Telerin. This was by some seen as a dialect of Quenya which was untrue in a historic perspective but plausible in a linguistic one; the languages did not share a common history but were very much alike.
The Noldor who fled to Middle-earth following the Darkening of Valinor spoke Quenya among themselves. However, when Elu Thingol of Doriath, who was the king of the Sindar (Elves of the Telerin line who remained in Beleriand instead of journeying to Valinor) learnt about their slaying of the Teleri, he forbade the use of Quenya in all his realm. The Sindar had been slow to learn Quenya anyway, while the Noldor at this time had fully mastered Sindarin.
Noldorin Quenya (Exilic) differed somewhat from Valinorean Quenya, because the language continued to evolve after exile, and it underwent some regularisation as it became a language of lore. There were also a few changes in pronunciation.