[Teomaderm]

If i had not mistaken the person who was reciting and memorising the Dukrin Karane grammar was doing so to get employed by the king and get a handsome income(correct me if wrong).
Adhi Sankaraarcharyas verse is to remind us to apply what we study with faith to aid us in the journey of spiritual upliftment and not just memorize verses blindly.
Learning of a language and grammar is never restricted at any age.
We should all learn the language which can call for God in any name that is the language of Love.