Parents' role

Well, this is an old study but relevant to social context for language learning:
Gardner, R.C. (1968). Attitudes and Motivation: Their Role in Second-Language Acquisition. TESOL Quarterly 2(3): 141-150.
http://www.jstor.org/pss/3585571

Parents have an active role: "monitors the child's language learning performance, and to the extent that he plays this role he attempts to promote success. That is, the parent watches over the child and makes sure he does his homework, encourages him to do well, and in general reinforces his successes" (141).

They also have a "passive" role: "attitudes of the parent towards the community whose language the child is learning". These attitudes are important, I believe, because they influence the child's attitudes" (141).

These roles can clash and the passive one undermine the active one. Of course the same applies to other significant others.