Psycholinguistics is not limited to adults. It also studies the ability of child and infants to understand languages. Psychology, cognitive science, and linguistics are the variant forms of Psycholinguistics that are studied at different levels. Early age scientists had very little knowledge about language production and understanding until Noam Chomsky published his research in the late 1950s. His work urged the other scientists to get a clear picture of language comprehension.
Psycholinguistics basically deals with the two questions as 1) how a human brain processes and stores language.2) what are means of language acquisition? Areas of studies in Psycholinguistics are Phonetics, Morphology, syntax, semantics, and pragmatics. There are still some issues in the field of Psycholinguistics whose questions are still to be confirmed. For example, Animal communication has a lot to offer in terms of language understanding how infants would be able to learn the language. Continuous research will definitely help the scientists to solve these issues.