Why does the Torah say that Lavan named the pile 'Yegar Sahadusa,' and Yaakov, 'Gal'ed'? Is this not a direct translation of Gal'ed?
Tosfos ha'Shalem (1): Lavan said to make 'Yegar Sahadusa,' a collection of testimony. Yaakov said that that the pile itself will be a witness, and Lavan agreed.
Malbim: Yaakov was concerned only lest Lavan harm him now, but not when he will be in his father's house. For this, a witness sufficed - 'Gal'ed.' Lavan was concerned how Yaakov will treat his daughters also for the future. He wanted lasting testimony - 'Yegar Sahadusa.' The Targum of Ed is Sahada.
Ha'amek Davar: Lavan did not understand that in Leshon ha'Kodesh, "Ed" also connotes testimony, therefore he called it 'Yegar Sahadusa' (testimony).
What is the level of sanctity of the words "Yegar Sahadusa"?
Shabbos 115b: 'One is permitted to save the Targum in the Torah - such as "Yegar Sahadusa" from a fire on Shabbos.' 1 Also, the Gemara in Megilah 9a explains that Targum that one wrote in Leshon ha'Kodesh is not Metamei the hands, 2 - implying that Targum that is written Targum is Metamei the hands!