Having informed us that Lavan named the pile 'Yegar Sahadusa', why does the Torah see fit to add that he called it 'Gal'ed? Is this not a direct translation of Gal'ed?
Ramban and Seforno: To teach us that he conceded to Ya'akov's wish that it should be called by its name in Leshon ha'Kodesh. 1
Tosfos ha'Shalem (1): Lavan said to make 'Yegar Sahadusa', a collection of testimony. Yakov said that that the pile itself will be a witness, and Lavan agreed.
In what sense was the pile a witness?
Rosh, Da'as Zekenim (52), Hadar Zekenim (52): They inserted a sword in the pile, and said that one who transgresses will be stabbed with a sword and stumble on the Matzevah. Bil'am, a descendant of Lavan, crossed with intent to curse Yisrael. His donkey crushed his leg on the Matzevah (see Targum Yonasan on Bamidbar 22:24), and later he was killed through the sword. 1 "The witnesses' hand will be first [to stone]."
Tosfos ha'Shalem (1, from citing Pirkei d'R. Eliezer 36): David could not cross to conquer Aram until he broke the Matzevah [even though Aram had already transgressed the Bris twice - Midrash Tehilim 60:1].