The aim of this paper is to examine W. V.Quine's theory of infants' early acquisition oflanguage, with a narrow focus on Quine's theory ofobservation sentences. Intersubjectivity and sensoryexperiences, the two features that characterise thenotion, receive the most attention. It is argued,following a suggestion from Donald Davidson, thatQuine favours a proximal theory of languageacquisition, i.e., a theory which is focused onprivate experiences as ultimate sources ofstimulation, contrary to a distal theory, where thestimulus source is located in externally observableobjects and events. I use the philosophical criticismof Donald Davidson, Dagfinn Føllesdal and CharlesTaylor to suggest an alternative account of languageacquisition, which emphasises the primacy ofparticipation and joint attention to external stimuli.I argue that such an alternative theory is moreconsistent with recent studies in child developmentand language acquisition.