Abraham was the first "Ivri", correctly translated as "Hebrew". However, "Hebrew" here refers to his nationality, not his language. Abraham was not the first person to speak the Hebrew language. The Hebrew language is the first language spoken by mankind, and originally the only language spoken by people, as it says: "וַיְהִי כָל הָאָרֶץ שָׂפָה אֶחָת וּדְבָרִים אֲחָדִים"(Genesis 11:1, see Rashi there). Until modern times, the Hebrew language was always referred to as "Lashon HaKodesh", the holy tounge, never "Hebrew", the language of the Hebrews. The names of all people in the Torah are written in Hebrew/Lashon HaKodesh, both before and after the introduction of the "Hebrews" onto the world scene.