Yes, this is a question that people keep repeating about comparatives, especially with these adjectives: easy, pretty, friendly, lively.
I know the rule about two-syllable adjectives ending in /i/ or /o/ should get the morphological -er and -est.
Yet, it is evident from different copora that the use of "more easy" and "more friendly" exists, which is not infrequent.
Did anyone come up with an explanation for this or did read any scholarly articles relating to the choice of these different construction of comparatives?