I was listening to a short meditative reflection by John Astin about language on the Waking Up app, and it made me realise that words are just a model of reality. You say tree, but in fact the word tree falls far short of the reality of a tree. It doesn’t tell you if it is tall or short, young or old, blossoming or in leaf. The word cannot encapsulate the reality of the tree, which always has more detail to be examined.
Also, what you see in your mind when you read or hear spoken language is a collection of impressions from the past. You may have a specific idea of a tree, tall, deciduous and healthy and in full leaf. But the author whose word tree you just read may have had a very different image and idea of a tree; it may have involved palm leaves and coconuts. So your impression of a read passage of words is pretty unique, based on the past encounters you have had.
Poetry deserves a special mention, because poetry is like an impressionist painting made out of words. It forms an image in your mind which is only loosely related to the actual words used.