Gamling
From Tolkien Gateway
The leader of the watchers of Helm's Dike, an old man, though still a commanding presence at the time of the Battle of the Hornburg. Despite his age, he was still a brave fighter - in that Battle, it was Gamling who first realized that Orcs had penetrated the Deep through its culvert, and he led the counterattack himself.
Gamling seems to have been brought up in the western valleys of Rohan - at least, he understood the tongue of Dunland that was still spoken in those regions.