Sindarin

(Eglathrin)^A) is a constructed language created by J.R.R. Tolkien for his Legendarium. It is the language of the Sindar – the Grey Elves – and, by the Third Age, is the dominant Elven language spoken in Middle-Earth.
It’s primarily written using the Tengwar in the Mode of Beleriand,^B) though it has also been written using the Cirth and a few other modes.

Sindarin is also known as the ‘Elven Welsh’ language.

Legendarium, Linguas

^A) The word ‘Sindarin’ () is, in fact, the Quenya name for Sindarin. ‘sfar as I know, Eglathrin is the ‘correct’ Sindarin term for the language.

^B) As far as I know, the Elves only ever used the Mode of Beleriand to write Sindarin. This is what all ‘canon’ information seems to indicate. Men were the ones who used the tehtar modes.