J.R.R. Tolkien named the Elvish language of Doriath Sindarin.
Sindarin is one of Tolkien’s major constructed languages. In his internal histories, it developed from the language of the Sindar, or Grey Elves, who remained in Middle-earth rather than completing the journey to Valinor. Doriath, the woodland realm ruled by Thingol and Melian, is one of its most important cultural settings.
Tolkien designed Sindarin with strong inspiration from Welsh phonology and sound patterns. It is related to Quenya within his fictional language family, but the two languages occupy different historical and social roles. Quenya is associated especially with the High Elves and has a more formal or ceremonial status in many settings.
The language is sometimes called Grey-elven in English descriptions. Sindarin is not the same as the language of the Dwarves, Khuzdul, or the speech of Númenor, Adûnaic. Tolkien revised details of his languages repeatedly, so some forms vary across his writings.