One of the reported instructions ‘Umar wrote to Abû Mûsâ Al-Ash’arî and those under his governance during the former’s Caliphate was, “Seek knowledge and understanding of (fiqh) the Sunnah and seek knowledge and understanding of Arabic.”
Ibn Abî Shaybah, Al-Musannaf Vol.6 p126.
Al-Bayhaqî, Shu’ab Al-Îmân Vol.4 p187.
‘Abd Al-Razzâq Al-San’ânî, Al-Musannaf Vol.1 p411.
It is also reported that he was once circumambulating the Ka’bah when he heard two men speaking in a language other than Arabic behind him. He turned to them and said, “Find some way to learn Arabic.”
‘Abd Al-Razzâq Al-San’ânî, Al-Musannaf Vol.5 p496.