From my understanding, you use "たち(達)" for plural living things, but I haven't had much luck trying to find out how to say plural objects. I feel like "tachi" isnt quite right sounding as someone who knows a decent bit of japanese (I can't really speak it, but i can read, write, and understand it). Does anyone know if there's something for objects especially? Unless it's tachi or gata?
My understanding (which may be incorrect) is that pluralizing non-living objects is not really a thing in Japanese, and even with living things it is often not done either. Whether one is saying "book" or "books" is based on the context, and at times it is ambiguous, but that is just an accepted normal thing. If one wants to really clarify things they can use noun counters.
For giving contextual clues, if one says "a few", "a lot of" , etc. in front of the noun, then it implies that the noun is plural.
Again, even with living things it seems to be pretty normal to not use "tachi" or "ra" even though one might be talking about a plural number of living things. And you would only "tachi" on a non-living object to suggest that it is somehow animate i.e. acts like a living thing.
たち・がた are not talking about plural in the sense that we think of it - they are referring to the actions of a group of people. So, if you are, for example, talking about the group of students waiting in the classroom, you could say 生徒たち. So they are used to emphasize the actions of the group as a group, if that makes sense.
