Answer:
Imitation theory: It refers to children's ability to pick up a language from their environment by mimicking adults.
Active Construction of Grammar theory:
It states that the children are born with an innate ability to understand and learn languages.
Reinforcement theory:It refers to reinforcement as a method of language acquisition.
Step-by-step explanation:
Imitation theory states that a person by birth has the ability to perform any act just by intimating the fellow people. In short, children by birth are good at copying activities of the native members. Thus, the ability to learn exists since childhood.
While as per the active construction of a grammar theory says that a person has the capability to develop linguistic features of any language.
Reinforcement theory defines the controlled behaviour of an individual with respect to its consequences. Therefore, a person has the ability to shape his/her behavior and learning.