Around the time of the Banu Nadir affair, if not slightly before, the Prophet ﷺ commanded Zayd ibn Thabit RA to learn Hebrew, wanting someone trustworthy to know the language. Zayd was chosen because he was young and sharp-minded, and because he had grown up around Jewish neighbors and already had some background in the language, having reportedly attended their schools.
Zayd ibn Thabit RA mastered both reading and writing Hebrew in fifteen days, showing both the eagerness of the sahaba and his own genius. He went on to become the primary compiler of the Qur'an.
Other events recorded around the same time. Their order within the year is not established; use the storyline above for the sequence.
I learned it in fifteen days: both reading and writing.
The Prophet ﷺ had instructed Zayd ibn Thabit to learn Hebrew, wanting someone trustworthy who knew the language.