This was his answer to what has become known as Plato’s Problem, or as Bertrand Russell summarizes it: “How comes it that human beings, whose contacts with the world are brief and personal and limited, are nevertheless able to know as much as they do know?” Being born with this knowledge from the get-go would naturally solve this little quandary and consequently he viewed language as innate.

Obviously these theories don’t touch too much on the practical, everyday level of language learning. They’re far less detailed and more philosophical than the modern scientific theories we’re used to. But they have important implications. If Plato and the Cartesians are right, then the emphasis in language learning must lie on what we already know, using our innate abilities to come to an understanding of the particularities of a specific language. If Locke is right, then we must focus our attention on sensory input, gaining as much external input as possible.

In the practical, everyday world, all of this can easily be done with FluentU. FluentU takes real-world videos with familiar formats—like movie trailers, music videos, news and inspiring talks—and turns them into personalized language lessons.

According to behaviorism, a radical variant of which was put forward by Skinner, all behavior is no more than a response to external stimuli and there’s no innate programming within a human being to learn a language at birth.

What differentiates Skinner from those who came before him is the level of detail he went into when connecting behaviorism and language learning. In his concept of what he called “operant conditioning,” language learning grew out of a process of reinforcement and punishment whereby individuals are conditioned into saying the right thing. For instance, if you’re hungry and you’re able to say “Mommy, I’m hungry,” you may be rewarded with food and your behavior will thereby be reinforced since you got what you wanted.

The theory that Chomsky proposed would be called Universal Grammar and it would assert nearly the exact opposite of what Skinner had offered in his theory. Where Skinner saw all learning coming from external stimuli, Chomsky saw an innate device for language acquisition. What Skinner understood to be conditioning according to particular events Chomsky, understood to be the result of the universal elements that structure all languages.

For instance, an immigrant is more likely to acquire their new target language if their language and the target language are socially equal, if the group of immigrants is small and not cohesive and if there is a higher degree of similarity between the immigrant’s culture and that of their new area of residence.