I doubt whether human beings are even a quarter of a percent as smart as we think we are. The indefinitely-extensible properties of logic and mathematics suggest that languages and intelligence on the higher end of the (Kardashev) scale are quite plausibly far too sophisticated for us to interpret or recognise; perhaps even indistinguishable from random noise. Machine Learning might give it a good shot but we would very likely end up with an indication that pattern exists without any clear indication of semantics.
We often assume intelligence, communication and life (or language) obtains some kind of pinnacle and paragon with our own ambiguously uncertain words, worlds and contingent meanings. A truth here might be that we and all we hold dear are really, as in the Copernican revelation, quite dramatically anything other than sited at the center of this system. We might be the outliers and dullards in a cosmos rich with life, complexity and communication of which our own minds and (as yet) primitive technologies remain blissfully unaware.
Arguments for probabilistic entropy and identifiable linguistic or communications patterns in extraterrestrial signals assume they will not be thousands or millions (or more) years ahead of us.