Motivation could be an issue. What if they do not want to communicate with us? What if we are too slow for them? Dolphins produce burst pulses that have interclick interval of just few milliseconds. We cannot even hear these individual clicks and for us the burst pulse sounds like a creaky door. But they, supposedly, can hear individual clicks. We do not understand or use echolocation, they do, so their "dolphin-socrates" probably would have their own allegory of the cave that is not based on what individuals can see.

Humans have the computers and machine learning experience. Why aren't they making software to figure it out? And dolphin/machine interfaces? Touch screens for elephants?

While that would be awesome, these foreign intelligences might have too little in common with our wiring to communicate in any way.

Also, we’ve been shaped by our tools since day one, and these animals use little or no tools.

We already talk to gorillas via sign language.

We’re pretty close to gorillas.

We’re very different animals from dolphins and elephants.

We may have nothing at all in common with extraterrestrial beings.

An overlap of concepts is needed for two entities to communicate.