Longitudinal structural equation modeling was used to evaluate longitudinal relationships across adjacent grade levels 1 to 7 for levels of language in writing (Model 1, subword letter writing, word spelling, and text composing) or writing and reading (Model 2, subword letter writing and word spelling and reading; Model 3, word spelling and reading and text composing and comprehending). Significant longitudinal relationships were observed within and across levels of language: spelling to spelling and spelling to composing (Grades 1 to 7), Models 1 and 3, and composing to spelling (Grades 3 to 6, Model 1; Grades 4 to 6, Model 3); spelling to word reading and word reading to spelling (Grades 2 to 7), Models 2 and 3; spelling to word reading (Grade 1), Model 2, and word reading to spelling (Grade 1), Model 3; composition to comprehension (Grades 3 to 5), Model 3; comprehension to composition (Grades 2 to 6), Model 3; and comprehension to word reading (Grades 1 to 6), Model 3. Results are discussed in reference to the levels of language in translating ideas into written language and integrating writing and reading. (Contains 6 tables, 3 figures, and 2 footnotes.)