In the old days, the first task of a young monk was mastering the Psalms. This meant memorization of all 150 Psalms.
If that sounds like a daunting task, it is nothing compared to what it would be like in our day. Which of the liturgical translations would be memorized?
Even worse would be any attempt to memorize hymns, the best of which have been altered by so many hands of varying capabilities that sometimes there is very little of the original left.