The present study examines private speech and strategy-use patterns for solving simple number fact problems in addition. The progressive differentiation by grade between children's levels of private speech internalization--including silence--was investigated and related to children's developmental patterns for subcategories of strategy-use internalization. Comparisons were made between 67 children with math difficulties (MD) and 67 children without MD from Grade 2 to Grade 7 in primary schools. Two separate laboratory investigations were performed for each child to examine private speech and strategy-use internalization. Analysis was based on private speech category differences, strategy-use differences, and differences in the occurrence of private speech-strategy-use combinations. Children without MD showed a grade-determined shift from less to more internalized private speech and from the use of backup strategies to retrieval strategies. In contrast, the private speech and the strategy-use internalization of children with MD, reflected in inaudible private speech and backup strategy use, seemed to converge at earlier developmental levels. The development of children with MD seemed almost to stop at the inaudible private speech-backup strategy combination level. The silence-retrieval strategy combination level was the primary alternative for typical math achievers. In all, the characteristics of the development curves of the children with MD were consistent with a developmental difference and not with a developmental delay model. Implications for intervention and future research methodology are discussed.