Musannaf Ibn Abi Shayba 13:3373

Abu Bakr narrated to us, he said: Abdullah ibn Idris narrated to us, from Abu Asim al-Ghatafani, from al-Sha’bi, from an umm walad (a slave woman who has borne a child to her master) who said to her master: "Your child danced when he cried for you," and he said: "Mādar-to-āzād" (Persian for: Your mother is free). Al-Sha’bi said: If he did not know what the Persian meant, then it is nothing.