This research examines the possible links between the presence of reflection markers and children's bilingual and monolingual communicative performance while carrying out a referential task. Reflection markers are conceptualized in a Vygotskian manner as private speech, and they are operationalized by the notion of informative fragmentation. A longitudinal study was conducted with 24 pairs of girls and boys, aged four to six years, using observational methodology The results show some divergence and similarities in the use of private speech as a function of linguistic group. At age six, the bilingual group performing the test in their mother tongue (moderate bilingual) presents more private speech, whereas the bilingual group that does not perform the test in their mother tongue (total bilingual) displays lower frequency of private speech. Messages of better quality were observed in the moderate bilingual and monolingual groups, and poorer quality in the total bilingual group. Among the similarities is the fact that the difficulty of the referent promotes the emergence of private speech in all the linguistic groups. In synthesis, if the task exceeds children's competence, the reflexive process is impaired, but this process can be regained as soon as a favorable situation is created in terms of communicative and cognitive control. It is concluded that private speech plays a relevant role in bilingual communicative development, an aspect that seems useful to explore.