Reading challenges occasioned by the third to fourth grade transition in South Africa's primary schools are well-documented, particularly in content area texts. Grade 4 reading heralds a shift from narrative text to content text reading, the latter credited with greater reading demands than the former. There is, however, dearth of research on how language texts, which are largely narrative, represent a linguistic complexity at the grade 3 and 4 interface. Using "English First Additional Language" grade 3 and 4 workbooks within the South African context, this research documents the extent of the linguistic complexity between the texts from grade 3 to grade 4. Both content analysis and readability formulas were employed to determine manifest factors impacting textual and linguistic complexity in two workbooks, and the workbooks' grade levels respectively. Content analysis evinced steep increase in textual complexity of all five factors analysed; and readability formulas revealed that grade 3 workbooks were higher than third grade level, and grade 4 workbooks' levels were slightly higher. This study recommends that workbook authoring be in accordance with research-based indicators of textual and linguistic complexity, with consideration of readability formulas in texts prior to adoption for use in schools.