How well animals can learn human words could depend on how attuned their hearing is to EQ curves in the frequency ranges that articulate vowels, and such. To so

How well animals can learn human words could depend on how attuned their hearing is to EQ curves in the frequency ranges that articulate vowels, and such. To some animals that hear well into ultrasound, human speech might just be a low-frequency jumble. According to some cursory web searches can supposedly hear past 60 kHz, possibly as high as 85 kHz, with a particular sensitivity in the 8 kHz region. That, to humans, is the start of the "air" frequencies where the sibilant sounds of speech are found.