Q: How have aircraft developed the ability of speech? (more specifically human languages such as English)
A: All the machine folk are very social creatures, and no more so in aircraft. It is beneficial evolutionary-wise to be social, as we can see in our own world, where the most advanced animals, wolves and other canids, cetaceans, primates, lions, just to name a very small few, are also the most social. Working together ensures more successful hunts along with the ability to defend such resources from competitors, and security, which also means lower infant mortality rates. All these creatures have varying levels of the rudiments of langu