[Maerbenn]

Eärendil seems to have known many languages. From The Problem of Ros in HoMe XII: The Peoples of Middle-earth:

In the havens of refuge, when Morgoth's conquest was all but complete, there were several tongues to be heard. Not only the Sindarin, which was chiefly used, but also its Northern dialect; and among the Men of the Atani some still used their Mannish speeches; and of all these Eärendil had some knowledge. It is said that before Manwë he spoke the errand of Elves and Men first in Sindarin, since that might represent all those of the suppliants who had survived the war with Morgoth; but he repeated it in Quenya, since that was the language of the Ñoldor, who alone were under the ban of the Valar; and he added a prayer in the Mannish tongues of Hador and Bëor, pleading that they were not under the ban, and had aided the Eldar only in their war against Morgoth, the enemy of the Valar.