Speech is part of our framework of capabilities essential for what we experience as normal consciousness. We have vocal apparatus that, together with our brains, enables language. Our complex hands allow us to manipulate our environment and perform complex abstractions and communication. For example, pointing at an object and making a sound represents "naming," which facilitates further abstractions. With language, memory, and storytelling, cultural development occurs, refining the tools and abstractions by which we engage with and understand our environment. Without dextrous hands, capable vocal hardware, or sharp eyesight, language and culture might not have developed, preventing the creation of machines that think.

Granting an animal the cognitive software of our culture means they only need speech to benefit from abstractions otherwise impossible to develop without humans.I focus on mammals due to the shared structure of our brains. Humans are conscious, and we must identify a specific phenomenon, network, circuit, or class of neurons responsible for consciousness. Since rat, human, and whale brains are incredibly similar, it's highly probable they have similar subjective experiences. We can't definitively rule out consciousness in different mammalian species due to our limited understanding of consciousness mechanics.

Some birds and lizards exhibit conscious and intelligent behaviors, suggesting different brain structures can serve similar functions. An Etruscan shrew has the smallest brain of any mammal, and there might be a threshold of capacity and architecture required for consciousness. If consciousness depends only on architecture, shrews might be conscious in a way we can relate to.

We don't fully understand consciousness yet; untangling the factors is a complex problem. Bayesian probability suggests that if your brain causes your subjective experience, other animals with similar brains are also conscious. Their behavior and artifacts, such as emotion, psychology, and intricate devices, indicate consciousness. Consciousness includes not just self-awareness or theory of mind but the second-by-second experience and interpretation of sensory constructs.

This idea challenges dualistic explanations. Religion, simulation theory, metaphysics, mysticism, and other explanations often arise in the absence of a clear understanding. However, one's conscious experience as a fundamental prior suggests a material basis for consciousness. Abandoning the bias of human exceptionalism is necessary for a cold, clinical view.

Consciousness seems to be a spectrum. Helen Keller described moving from a continuous, borderless blur of experience to concrete, episodic sequences with clear self-other delineation. Primitive humans, biologically similar to us but without language, would have experienced life differently - much like Helen's pre-language blur of the eternal now. Whales and other large-brained mammals might experience life similarly. If we discover their language, or a way of mapping engrams of their experience onto language, it will reflect a different way of experiencing things. The same applies to forests, giant mycelial networks, and colony insects, where we might find the computational circuits underlying consciousness and cognition.

We don't get to explore those things if we insist on staying in the cave and theorizing; I'd love for someone to point out I've wandered down a dead end, but everything I've read and considered so far leads me to believe that there's no value in distinguishing one's own consciousness from all other things scientific. Treat it as the evidence it is; if you need to update, update all the way.

So..."I know you're wrong but I can't/won't say what about, how or why I know it, or otherwise back up my claim"?

This sounds like just another way of saying "I don't like your conclusions, but I can't see a good way to refute them."