I (i.e. Abū Ḥamza) heard Abū Muḥammad (al-Ḥasan al-‘Askarī) speaking on more than one occasion to his servants in their own languages. Among them were Turks, men from Byzantium and from Ṣaqāliba (in the Caucasus).
I was amazed at that and I said: “This man was born in Medina. He did not show himself to anyone until Abū al-Ḥasan (al-Hādī) died, and no one saw him. How is this?”
I was saying this to myself. He came up to me and said: “Allāh has separated His proof (to the world) from the rest of His creatures and has given him knowledge of everything. He knows languages, genealogies and events. If it wasn’t for that, there would be no difference between the proof and those who are given the proof.”
(Kitab Al Irshad, Chapter on Imam Hasan Askari (a.s.)Al-Kāfī, I, 509, tradition no. 11)