Starting with a model for explaining comprehension and noncomprehension of verbal material in terms of a match/mismatch principle, this project developed a scale of language usage and explored hypotheses about how comprehension may become possible if a child does not now comprehend some particular oral or written text. Eight separate reports are included. They discuss the development and testing of the scale; the likelihood that a child will comprehend a text of lesser, the same, or greater complexity than that usually used by the child; the possibility of increasing the comprehension of complex materials by introducing redundant features; the effects of "associativity" as a form of redundancy and as a factor in comprehension; the language features of experienced and inexperienced caretakers of nursery school children; and the effects of these features upon the children's language production. (Author/AA)