"And We certainly know that they say," meaning the polytheists of the Arabs, "It is only a human being who teaches him." They mean a slave of Ibn al-Hadrami, who was a Roman [Byzantine] man possessing a scripture—according to the tafsir of Qatadah—whose name was Habr.
Others said: It is Addas, the servant of Utbah ibn Rabi'ah.
God said: "The tongue of the one they incline toward," meaning they lean toward him, "is foreign, while this is a clear Arabic tongue," thereby proving them liars.