The words for spirit, breath, wind, energy have related meanings in both the Semitic and Indo-European language families. I have indirect reason to suspect that this is not untrue about the Uralic (Finno-Ugric) languages as well but do not insist on it. There was interaction among those in prehistoric times, so it may be that there was concept-borrowing rather than a common origin. Yet it is so pervasive in both sets that I consider this unlikely. More likely this unity was present beforehand, whether because it is a human universal or because it at least derived from the murkier earlier versions of those language families, back into the Eurasiatic or Indo-Semitic languages. Be it noted that those categories are worse than just speculative - more like generally rejected by linguists - and describe possibilities long before writing or clear associations we can track now, so I wouldn't ride that horse too far away from known sources of water.
Yet there they are, related meanings between families where no related meanings should be. Owen Barfield believed these pointed to earlier concepts in language that were not merely related, but in fact unities. When ancient man thought of -pneu or ruach he did not do so in a manner we might in our day, "oh, that word for breath could also mean spirit or wind or life-force - those are interesting poetic connotations," but understood the word to mean all of these at once. We have divided things and made them more specific, and this is useful in so many ways for our understanding and precision, but it necessarily loses that unified meaning. Our theories of language origin have centered around moving from the concrete "That's a rock. He is throwing" to abstract meanings like attributing deity to a river or metaphors of enclosure/completeness leading to the name for the wheel. Barfield reverses this and claims that the metaphors were there from the start, and were the earlier reality. It has been called his greatest insight and contribution, "not merely a theory of poetic diction, but a theory of poetry, and not merely a theory of poetry, but a theory of knowledge" and the arising of consciousness.
He reasoned from his observation that as we went back as far as we could in the languages we knew, we did not find them getting increasingly concrete, but increasingly mixed, metaphorical, multi-meaninged. I don't have anything like the linguistic knowledge to confirm or refute this, and I think the little attention my textbooks paid to the subject sided with the other theory, of the concrete giving rise to the abstract. Yet is should be said that he had thoroughly convinced the great linguist Tolkien of this idea by 1928, and Tolkien's letters reveal that his whole legendarium took a new turn at that point, and regarded his writings as proof-of-concept for Barfield's theory here. When Tolkien uses light in LOTR, or especially in the Silmarillion, he wants many meanings to be present at once: the ability to see physically, the ability to perceive spiritually, the aggressive pushing back of the darkness, the illumination of knowledge, the combined joy and pain of brightness. Think Galadriel's phial as a good example.
Tolkien knew a great deal of the origins of the Indo-European, Uralic, and Semitic languages and did not take issue with this idea that they become more metaphoric, not more concrete as we trace them back. In the absence of any knowledge of my own, I have to accept this as evidence that Barfield is at least not ridiculous and impossible here. Barfield thought that as consciousness fought its way through to arise, the idea of deity was not added to the river, but a world of spiritual powers was gradually discerned. The river, as it was recognised, already had a spirit.
To take another example, consider an intelligent animal like a dog, which we might think of as having some consciousness trying to arise. The dog has few understandings of what we call a word, or a concept, yet it does have this whole interconnected array of concepts of having a master, being a good dog, wanting to please, all being right with the world, there being no pain and enough food, affection, and running. It is all one in the dog's mind. It takes much greater powers of distinction to be able to sort out "The world is not right because I am hungry," or "not right because my master is not here," or "not right because I did something wrong this morning that I don't remember." Given that picture, consciousness rising in primitive man could have happened that way.
We have gained more than we can even describe, yet we have lost something as well, some poetic and spiritual connection of all things. It is nearly unrecoverable, though poets and artists can bring us some of it.
Tolkien, Barfield, and eventually Lewis and Williams regarded these sorts of associations as True Metaphors, associations which are not artificial and forced, but capture an ancient reality. Things that are flowing, fleeing, flying have some underlying reality that is reflected in the language but are, in some deep wood long uninhabited but once a home of elves, actually the same thing. Breath and energy and wind and alcohol and the Holy Spirit share an underlying reality.
I don't know if I quite understand this or accept the truth of it, yet it seems to be what is happening in Middle-Earth.