Quint i.4.22: Nomina declinare et verba in primis pueri sciant: neque enim aliter pervenire ad intellectum sequentium possunt…
In the various pedagogical discussions involving CI and TPRS, it’s interesting to note that Quntillian here seems to advocate memorizing noun and verb paradigms (lit. “knowing how to decline…”). Simpliciter dico… 
For native speakers of French (I assume it’s the case for other languages as well), memorizing conjugations is a normal part of elementary education.
However, by the time they receive that ‘elementary’ education and start memorizing those paradigms they already are native and fluent speakers, and have been for several years…
CI definitely acknowledges the role of learning paradigms etc. as monitor (see monitor hypothesis), but only after acquisition of the language (via TPRS or other means).