> That means this has more to with ability to communicate/signal your consciousness.
Communication is the only data you have to support the theory that there are conscious beings other than yourself. Hypothesizing a conscious being that can't communicate at all (not to be confused with the temporary inability to communicate brought on by sleep or locked-in syndrome) is like hypothesizing an invisible leprechaun living in your pantry.
Then the real problem is how do we communicate with a rock?
Without the ability to communicate, consciousness means nothing at all. Then of course communicate how? Hand signals, hand writing or voice are equally mystical forms of communication given that these are waves(light and sound). That's already Telepathy category. We just don't feel it as magical because every one can do it.
I'd imagine for a humanoid species without ears or even a idea that something like sound wave would exist, talking would be synonymous with Telepathy.