Earlier quoted context omitted.
The difference is that we are able to accumulate information across generations to grow our collective knowledge. Other animals are not able to do that at scale. So, while you are correct that other animal communicate and even teach each other, it's a qualitatively different situation from human communication.
We really don’t know this for certain at all. We do know crows can communicate information about the face of a person they dislike to their murder, including to new generations. It seems a bit of a stretch to say their cultural transmission is quite that narrow. In general, pre-writing human oral culture seems to have dynamics much in common with such abilities in other animals. Barring error correction mechanisms, o…
The language itself is a a human invention, and a product of how our brains are wired. However, there's a dialectical process here where the language shapes us in turn, and both our minds and our language evolve together. The reason we have more things to say stems from us accumulating knowledge and expanding out horizons through the use of our language.