A Rudimentary Description
Everything that physically exists is a part of reality. These are the things that we can see, touch, smell, think about, or talk about, as well as the things that remain hidden from our senses. There are things that physically exist regardless of whether or not any sentient being can sense them. The ink on this page and the arranged electrons on my computer screen exist in this reality.
What can then be considered (by minds) as a second realm of reality is a subset of the complete reality – that first reality. What exists within this second reality is real too, but only in brains. These are the physical manifestations of belief – neurons and neuronal connections, themselves comprised of brain matter. These are labeled with words such as thoughts, memories, feelings, perceptions, and attitudes. These are how our brains perceive everything in the first reality, order these perceptions, interject them with emotions, instincts, and categories so as to interpret the world primarily to predict the best future courses of action. Most animals have these beliefs because most animals have choices. Beliefs inform choices, the results of which cyclically shape belief.
The constituents of language, then, can be considered a third reality. All language exists in the first reality as ink on a paper, or electrons on a screen, or sound waves created by vocal cords. Crucially, though, all language also must exist in the second reality. All language depends upon prior belief, which itself depends upon prior reality.
Conversely much of reality exists without belief, and much of belief exists without language, including all belief outside of people – i.e., animals.