I believe all animals definitely have some sort of language, and that the complexity of a language depends on its utility in facilitating everyday interactions and activities. What are the most complex activities you've seen elephants get up to?
Now, from what I've learned/read about their behaviours, I have no doubt on the depth of their lives. https://en.wikipedia.org/wiki/Elephant_cognition#Elephant_so...
And I wouldn't call that "some sort of language". That's language. Species-specific. Not "human" language.
Even language that another species can grasp more or less perfectly. You can get that with minimal observation of dogs, cats, even birds. And obviously, animals read us as well.
Now, the complexity of an other species language may be partially out of reach because we do not have the same senses, abilities, history, memories.
So they might even engage in activities we cannot grasp or identify (and reciprocally) but for great patience, observation, study, understanding, and luck.
Kind of makes me think if we ever were to encounter extraterrestrial intelligence we might have trouble identifying them as intelligent, or, have trouble communicating with them, because we have trouble identifying and communicating with the terrestrial intelligence that surrounds us and is abundant.
Where No Wolf Has Gone Before.
This happened in a remarkably short period of time, and the running theory is that early dogs with more expressiveness were better cared for and received by human societies than similar dogs that were less expressive.
I agree that there may be a lot happening in this world we're unable to perceive, and then your whole argument can be summarized as "anything is possible, we don't really know for sure".
Which I now see is why scientists insist on sticking to things that can be measured, proven and quantified. Anything else is drifting into the territory of religion, superstition and imagination. Humans have been known to worship certain animals as supreme gods after all.
No. Science is a mean to an end, not an end in itself. And intuition, an open mind, imagination help a lot, without drifting into superstition.
Read some history, you'll find out that a lot of scientific (and engineering) discoveries were triggered by imagination servicing some more rational/rigorous practices.
I don't think that's what they mean when they say imagination: imagining things we can not imagine. And science starts with real imagination, then move on to practical, measurable applications.