This is wild. Crows in this study could tell that recordings of people speaking Japanese (the language of the researchers) was different from recordings of people speaking Dutch. We can’t do that listening to birds. Unless we were a highly trained specialist, we couldn’t distinguish between mockingbird songs in one part of the country from mockingbird songs in another part of the country, though each song has a ‘dialect” that makes them mutually unintelligible. All the mockingbird would know is that another mockingbird is yelling at it. It has to learn to sing in the local dialect (meaning mockingbirds have learned cultures, actually.) But when a crow hears recordings of humans speaking different languages, it can tell that we are not speaking the same language, and it reacts to them differently. They were used to Japanese. They were wary of the recording in Dutch. What were they hearing? Japanese isn’t tonal like Chinese, so it’s not that the crows can tell that one is melodic and the other not. Can they detect the different phonemes (the vowel and consonant sounds) the languages use? Can they distinguish stresses, like what part of a sentence rises or drops? Can they detect the specific rhythms or sound patterns of grammar? How is it that a goddam bird can tell if a person is speaking Dutch or speaking Japanese while we with our enormous brains can’t tell if a recording of a mockingbird screaming at five in the morning is in Southern California Mockingbirdese or Danish Mockingbirdese? I can write about the concept of a crow distinguishing human languages, but damn if I can imagine what it is they actually hear in our human sounds.