What's interesting to me is that we use the same morphological operation (-s suffix) to express two very different concepts. You see this in other places as well, for example the Germanic -en suffix is used in at least 3 different ways in English: as the past participle verb tense (speak -spoken), as a way to transform adjectives into verbs (wide-widen) and (a very old) way to transform nouns into adjectives (gold-golden).
Why not use different morphology for these different grammatical concepts? The language would be cleaner and more consistent. My theory is that, basically, it's hard to learn to pronounce many different sounds, but it's easy for our brains to sort through the ambiguity that the morphological overlap produces.
Why not use different morphology for these different grammatical concepts? The language would be cleaner and more consistent. My theory is that, basically, it's hard to learn to pronounce many different sounds, but it's easy for our brains to sort through the ambiguity that the morphological overlap produces.