This is just my own personal theory, but one reason is that we just scoop animals up, put them in a room, and expect to try finding speech patterns. What would

This is just my own personal theory, but one reason is that we just scoop animals up, put them in a room, and expect to try finding speech patterns. What would happen if a flock of hyperintelligent pigeons found some human babies and locked them up in a room until it's time for snacks and games? There probably wouldn't be much language observed aside from a few repeated sounds. Another is aside from insects and humans and maybe some birds, not many creatures have multi-generational, continuous societies grounded in one region. Humans have towns, cities, and countries. People have had their entire family history confined to one town or one country with interconnected cities for centuries or even thousands of years. This lets humans develop a common means of communication between others who we see frequently or between those who share a similar background. A lot of animal groups get pretty divided and don't live in large and everlasting packs. There's not much evolutionary pressure for complex language to evolve. We don't even know when humans first developed languages capable of expression of abstract thoughts, but it was probably sometime after we started to organize ourselves and cooperate to form lifelong communities. The last one is that even if animals had a language, our brains just might not recognize it. For example, to many Europeans, picking up the idea of a tonal language at 40 is pretty tough. They might not even notice the difference in sound. Animals might have some way to distinguish words that we're just not looking at. I think this is one time where the recent ML/AI surge might come in handy. Record thousands of hours of animal sounds and put it through a black box. We've identified some sounds from prairie dogs as carrying meaning, but I don't think we've managed to identify grammar or sentences yet.