The debate over animals thinking reflects the more fundamental debate on whether thinking presupposes language. My experience of 29 years as an English teacher is that there is no correlation between consciousness and language expression.
People are wonderfully creative in how, when and why they express themselves.
When it comes to blank stares in the classroom, there are plenty of more convincing causes than verbal inability. Privacy Information Stay connected to the news that interests you with free e-mail alerts from The New York Times.