Sorry, this little essay is a “mouthful” yes. But that’s the point, you see. Please read to the bottom.
All of Essay Thirty-five in Darwin, Dogen, and the Extremophile Choice.
When we claim to describe what’s Really going on by our words, no matter how beautiful, such words are already in error. Truth simply cannot be re-presented. We want Truth badly. We want to hold it tightly in our hand … to give it to others in a word or phrase. We want something … we can impress upon others—and impress others with. But Truth is not like this … We only need to see that it’s beyond the spin of paradox that Truth and Reality are glimpsed. If we would simply not try to pin Reality down, confusion would no longer turn us away. —Steve Hagen 
From a motor-sensory phenomenological perspective, language seems to operate as a closed field of associated behaviour that helps to organize and extend the more intricate and practical non-language covert behaviours it aligns with. In practice, what this means is that arbitrary linguistic behaviours branching off from innate roots (genetically encoded, but not yet socially calibrated, behavioural routines: facial imitation, babbling, etc. [bonobo infants babble, but they are probably now competitively excluded from our technological niche] that have been enhanced and adapted, on the phylogenic scale, in response to the selection pressures of persistent learning-acquired structural-tool-use) are learned in parallel with our non-arbitrary cognitive behaviours. This closed field—meaning every-interior-thing gets mapped onto, or symbolically replaced by, a perfect (meaning it appears to be sufficient unto itself) behavioural layer generally limited to the mouth and throat—was probably at first an energy-conserving overt, and eventually a covert, persistent means (a tool) for finally liberating the un-Natural artefact potential of the human body from the conformity imperative that assures ecological stability in normal times. Language behaviour supports this ‘cultural escape’ by associatively tracking, maintaining, articulating, and outering (a ‘palingenetic’ variation of the word ‘uttering’, often used by McLuhan ) the more complex, seamless, and truly reflective (non-arbitrary) subtle-body behaviour sketches and memory traces we call “thought”. (See?)
But perhaps our analogy (conceptual evolution vis-à-vis biological evolution) can make this mouthful easier to digest: words are to thought-behaviours as red breasts are to robins, they are the means to a faithful reproduction of type. Furthermore, words are not only similar in being traits that are useless outside their purview of cultural specification but, like showy inbred feathers, they can only contribute to cultural ‘species’ by exposing their owners to a far more voracious creativity.
1. Hagen, Steve. 2004. Buddhism is Not What You Think: Finding Freedom Beyond Beliefs. San Francisco: Harper Collins. p. 5.
2. McLuhan, Marshall. 1964 Mentor paperback second edition. Understanding Media: The Extensions of Man New York: McGraw-Hill, p. 222 for example.