A social conditions influence the opportunities that learners have to hear and speak the language and the attitudes that they develop towards it.
B second language acquisition can be defined as the way in which people learn a language other than their mother tongue only inside a classroom.
C the systematic study of how people acquire a second language is a very old phenomenon belonging to the second half of the seventeenth century.
D ‘second’ cannot refer to any language that is learned subsequent to the mother tongue, thus it cannot refer to the learning of a third or fourth language.