alt Hacker News> Before language was invented the only way information could be passed down from ancestors to offspring was via mutations in our DNA.
Language (in the sense of "use of language appears around 100,000 years ago") is not the only way to communicate information, and many animal species are perfectly capable of communicating information despite not having evolved what is being called "language" in this sense.
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.