I know that some adjectives can have two comparative forms, and I'd like to ask you which of them are the most common in your region:
- cleverer or more clever;
- simpler or more simple;
- narrower or more narrow;
- shallower or more shallow;
- quieter or more quiet?
I'd say: more clever, simpler. more narrow/shallow/quiet.
Thank you in advance
All the "more____" and "_____er" variants that you give are o.k. in the English that I speak. I would probably subconsciously usually choose the "________er" form first. "Cleverer" might prove less frequent than "more clever" for some people (if anyone were ever to keep count) just because of the difficulty or awkwardness in pronouncing "-erer" at the end of the word.