1) Infants develop cognitive abilities in the first two years through sensorimotor intelligence, where they learn about their environment and objects through their senses and motor actions. 2) Information processing theory views infant cognition development through an analogy to computer data processing, finding capacities for intellectual concepts by 6 months through memory, perception of affordances, and preference for movement and people. 3) Language develops through listening, babbling, first words around 1 year, a naming explosion at 18 months, holophrases and sentence intonations, and theories combine nature and nurture aspects of innate and social influences on language learning.