title: Cognitive stage differences in types of speaker uncertainty markers.
mesh_terms: D000293:Adolescent; D002648:Child; D002663:Child Language; D002675:Child, Preschool; D003071:Cognition / Q000502:physiology*; D006801:Humans; D007804:Language Development; D008960:Models, Psychological; D011336:Probability; D011581:Psychological Tests; D013060:Speech