According to Wikipedia, Speech Perception is defined as "the process by which the sounds of language are heard, interpreted and understood." Speech Perception is also linked with phonetics and phonology in linguistics ("natural language") and cognitive psychology (mental processes) and of course, perception in psychology.
What I wanted to learn more about was Infants and how they learn about speech and language. Infants begin this process by being able to detect the very small differences between speech sounds. They can discriminate all possible contrasts (phonemes). As they are exposed to their native language, their perception then become "language-specific." (This means that they can learn to ignore differences that can be contrastive in other languages).
There have also been some researchers who have proposed that infants may be able to learn the sound categories of their native language through passive listening, using this proces called "statistical learning."
Watch the video below as the psychologist explains how scientists have developed tasks to understand the infants and how they percieve things. The most important times, we learn, are during the first year of life. Enjoy!