Aldudénië
From Tolkien Gateway
(Quenya for "Lament for the Two Trees")
A poem lamenting the death of the Two Trees, composed by Elemmírë of the Vanyar, soon after the event. Famous to all the Eldar but not recorded.
The name is problematic for the Tolkien scholars, because the sound "d" doesn't exist in Quenya (only the "ld" and "nd" diphthongs are present). It might be some idiom of the Vanyarin.