language and the brain with which to use it

I was going to be vague and say "the brain" but other things have brains. Our advantage comes from our vast capacity for abstract thought and the ability to communicate these thoughts effectively between individuals.

As with most other things in evolution it's a fairly flukey combination of circumstances which allowed this to happen. Walking bipedally freed our hands, the use of tools coupled to the development of the extra-pyramidal pathway permitted us to use our fingers one at a time, a vertically-supported head (which (being fed on energy-rich cooked flesh) didn't need such massive grinding teeth (and could therefore have a smaller jaw and more delicate structure)) could develop a larger brain pan, a valve in our throat could also be used to produce sounds in the range our ears can detect and sufficient selection pressures were present in order for all these and more to gradually synergistically develop into the ability to speak, write and have something to speak and write about. Evolution has no foresight and never intended language/abstraction/communication to develop but individuals which learn to shriek when they see a leopard and run when they hear a shriek are more likely to live to reproduce than similar creatures without such co-operative behaviours.

Plenty of animals can communicate perfectly well without such a complex language but the ability to think outside the moment and share ideas must have been a massive help for early hominids. It's one thing to see a food-animal and scuttle after it, another to see the animal, tap your hairy colleague on the shoulder, point at your belly then scuttle after it together and quite another thing again to say "I'm feeling a little peckish, Thog. How about you and I fashion a couple of crude spears from those sticks over there then climb and wait in that tree above the nice leafy plants on which the antelopes habitually graze in the afternoons?"

Plenty of cultures survive perfectly well without going too mental on the written-language front although written language does exemplify the concept of a grammar and structure necessary for the specifics of communication. Pointing at the belly can mean "belly full of food" or "belly requires food" or "I wouldn't touch those eggs if I were you"; moving beyond simple gestures expands the capacity of a language enormously although gestures are capable of distinguishing different points in time such as the future-present-past time-line beside the head in modern sign language. Verbal communication evidently pre-dates written communication although verbal communication prior to the invention of the telephone was always limited to person-to-person direct interaction between individuals and is therefore a relatively fragile process.

On the other hand our current memory capacity was both encouraged by and vital to the use of verbal communication. Think how much data computers use to store music but how easy it is to remember every note and tinkle of a piece in your head; it would be interesting to know whether the brain stores music as sounds like a .wav file or as a series of sound-concepts (be they words or notes of a particular instrument) in a particular sequence like a .midi file.

Maybe if we'd gone straight to written communication we wouldn't need to remember as much as we could just write it down then effectively forget the specifics although it is obviously important to remember what had been written down and where it had been put. As well as remembering things we also need the ability to think about things, often several things simultaneously and it's this mental bandwidth coupled with the ability to store and load different concepts which allowed the (relatively) recent explosion of invention and (tool-based) development. Isaac Newton's crack about the shoulders of giants (which he actually borrowed from someone else) makes the point very well. He didn't need to perform that many experiments in optics as plenty of others had done so beforehand and recorded the empirical data.

Plenty of things get by perfectly well without written language, abstract cogitation and high-speed complex verbal communication though. We could be said to be fighting a losing battle against bacteria and viruses, neither of which think too hard about what they do but just are whether they're simply evolving methods of piggybacking on a cell's protein synthesis mechanisms in order to pass on their genetic material or simply expressing the lipopolysaccharide on their outer surface which their genes determine they must express on their outer surface, no matter what the terrible consequences are for the organism inside whom they live.

Still, for relatively small, slow, weak, dependent primates we at least have other abilities to aid our survival. The pen isn't always mightier than the sword (nor can the tongue always lick the fist) but no-one would know who the sword attacked nor by whom it was wielded unless someone wrote it down.