It was reported that Koko understood approximately 2,000 words of spoken English , in addition to the signs .
In contrast to other experiments attempting to teach sign language to non-human primates , Patterson simultaneously exposed Koko to spoken English from an early age .
Koko was reported that Koko understood approximately 2,000 words of spoken English , in addition to the signs .
In contrast to other experiments attempting to teach sign language to non-human primates , Patterson simultaneously exposed Koko to spoken English from an early age .