What's the difference between particles と and も？

Question

From what I understand, they both can mean "and" and "also" or something, but I don't entirely get the difference. Please try to explain in as simple of terms as possible!

Answer 1

The first point to note is that the particles も and と have many different uses other than the ones you mentioned, so don't be surprised if you see them used in ways that don't fit this discussion.

When と is used to mean 'and' it denotes exhaustive listing. So if you say:

犬{いぬ}と猫{ねこ}がいる。

It means that there is a dog and a cat and nothing else. In contrast if you replace と with や it would mean that there is a dog and a cat and maybe some other animals that I haven't mentioned.

I can't think of any case in which と could be used to mean 'also'.

も can mean 'also'. For example:

私{わたし}も猫{ねこ}が好き{すき}
I like cats too. (I, in addition to someone else, like cats)
私{わたし}は猫{ねこ}も好き{すき}
I like cats too. (I like cats in addition to other animals)

も can mean 'and' if it appears more than once:

犬{いぬ}も猫{ねこ}もいる。
There are both cats and dogs.

Which is equivalent to "There are dogs and there are also cats", so it still has a meaning of 'also' as well as 'and' in this context.