There are a number of authors that talk about the leaning of a second language; the most important authors about thesetheories are Piaget and Vigotsky. Both are innate constructivist, but everyone has different theories about the child learning, and how the children have builthis learning, socially or individually.
Vigotsky talks about a social constructivist way, therefore the s knowledge is from the outside in, consequently thechildren are influenced by themselves to through their collaboration; in this case they are like a mediator between them, and consequently the learning isgiven in an interpersonal way and after it going to be in an intrapersonal way.
Piaget: he talks about innate constructivist way to learn a second language; heexplains that the child can built his knowledge is inside out, therefore he holds on in his theory that among peers, they can only learn internally and notsocializing like says Vigotsky in his theory, therefore with the innate constructivist way causes a restructuring of thought in the child (assimilation,accommodation, and equilibrium): consequently the learning is going to be in an individually way.
Finally Piaget and Vigotsky talks about a constructivist way to learn,but from a different point of view, but their objective is to guide about how the children can to learn in different contexts and in different situations, andthe most important thing is to know that not all children can learn in a same way like others, therefore they need different things and strategies to learn.