Would you agree the "describing" issue you raise is the same as "English can describe what it feels like to be pinched, but cannot make you feel a pinch"? No dolphins are needed, it's the issue of qualia.

A universal language can express anything that can be expressed in language. If qualia are outside the realm of language, that wouldn't make English less universal.

You may say dolphins use a language, and then feel qualia in response. Similarly, we can imagine a human who is genetically engineered for his skin to pinch when he hears certain sounds, so that he would feel the pinching quale. I think in neither case should triggering hardware features by sound be considered language. A nice example is "clap on" devices -- surely that's not language.