Neurons have lots about them that is innate. But, of course, human brains can learn any language, so the neural networks for speech can't be completely hardwired. Even the physical density of connections has been shown to vary significanty as a function of experience. The most obvious thing is that it involves the conscious experience of what is to be learned. To learn anything requires attention.
Young children have notoriously short attention spans.
Not suprisingly, the conscious continuity of episodic memory does not begin to emerge until 2 or 3 in most of us, and learning probably parallels this trend. I have conjectured that the TIN constitutes the neural substrate for a cortical global workspace. Obviously the data is still out on that one, but I think it is a testable hypothesis. The myelogenetic cycles of regional maturation of the brain. Regional Development of the Brain in Early Life .