Our nearest primate relatives, Chimpanzees and Bonos have a simple language. With training they can learn around 50-200 words, mostly in sign language because they dont have the capacity for modulating complex sounds.
Right, Lykan, language must have evolved because there was a need for it. According to present theory, the primates that ended up as us were living in the forests of eastern Africa some 6 million years ago, and they were probably living more or less like chimps are to-day. But at that time, the Great Rift Valley was being formed, and as it broadened, a new habitat was created, namely more savanna-like areas.
Apparantly some of those primates started exploiting this habitat, hunting systematically for food (chimpanzees are known to hunt occasionally). But for a slow primate with small teeth and no claws to hunt effectively on the savanna, cooperation and weapons are needed. This is believed to have provided a strong selectional pressure towards increased intelligence and, probably, language.
I think that once intelligence had developed to a certain level, it became self-reinforcing; it gave the adaptive pre-hominids the ability to expand further into new habitats, and this in turn favored more intelligence, etc. -- until we reached our present, vastly advanced level, where we can use incredibly complex technology for idle chatting and bickering, heheheh.
Hans