Language is the basis for all our knowledge, no?

Perhaps yes and no (or "ja/nee").

Reed has written a facinating and insightful article on language acquisition, which blurs up the distinction between ontologies and ontogenesis really well.

Some reasons why it might be interesting:

It deals with the most fundamental learning, the acquisition of language, which is also the most fundamental transition into learning and into a community of practice and a community of inquiry. Its the best metaphor and framework for transitions that I have come across. From a Montessori perspective it is really stunning, as it validates the ("silent learning") work that Montessori developed, informed by Piaget, but also partly by instinct. Its also about the boundary between the individual and social groups (in action and in communication)

What attracts me about 'affordances' is that affordances give me a way into what Good (2007, in Theory and Psychology) calls the "intimacy of mind, body and world", see:

"Much work is already underway and there has been a remarkable convergence of the ideas of ecological psychologists, mutualists, cognitive scientists, philosophers and neuroscientists in their attempts to explore the consequences of a recognition of the intimacy of mind, body and world".

... which is a theoretically rich framework for exploring how people learn - through perception/ action/ cognition/ reflection/ creativity.