I am curious if there is any reason that English converged to using similar suffix for both comparative adjective, and for noun. For example, as shown in the title, "cleaner" could mean both the person who cleans and as an adjective, a comparative of clean.
In the pursuit of the answer, here are some of the observations that I made:
Can I say that this only happens when we "noun-ify" verbs which are also adjectives? As another example, "fit" is both an adjective and a verb. "Fitter", hence would be both a comparative-adjective and a noun.
The -or suffix usually refers to the person performing the verb in question. For instance, act and actor. Maybe the "-or" prefix comes to be "-er" only when the nounification of adjective-verbs is performed?
For completeness, my question is this: Is there a reason for why it's not "cleanor", or "fittor"? I am also happy to know if there's a consistent pattern of where "-or" is replaced with "-er", while understanding that absolute consistency and language don't necessarily go together. :)