Abstract : Interactionist (Vygostki, de Weck) and dialogic (François) approaches of language acquisition assume
not only that dialogue and/or interaction play a determinant role in language acquisition but also that
forms and structures cannot be understood without referring to discursive practices. Whereas
communicative experience is a central concept in most non nativist approaches, for the needs of
arguing or demonstration some aspects may be more often foregrounded than others and the dialogic
dimension can end to be unaddressed. After brief presentation of usage based approaches, this paper
contrasts grammatical acquisitions under the light of cultural and social roles and their expression
through activities. In the last section it proposes some hints of the way dialogue (and not simply input)
is not only the context but also the vehicle for the acquisition of referring expressions, their referential
value and their use
