Paraphrase to simple English and make it short:

Innatist perspectives emphasize the role of genetics and biological factors in shaping language acquisition, as opposed to environmental factors such as imitation or reinforcement (Kuhl, 2004). Proponents of this view argue that the speed and universality of language acquisition cannot be solely explained by exposure to language input, but must involve some underlying cognitive mechanisms that are specific to language learning.

Innatist perspectives focus on how genetics and biology influence how we learn language, rather than copying others or being rewarded for learning. They believe that our ability to learn language quickly and universally cannot just be from hearing others speak, but are due to specific mental processes for learning language.