Background. Previous research in linguistic development in writing has primarily addressed the acquisition of writing, early linguistic development of writing, and spokenwritten interactions in the primary phase. This study explored linguistic development in older writers in the secondary phase.Aims. The aims of this 2-year study were to investigate both the linguistic constructions in secondary-aged students' writing, and to explore their understanding of their own writing processes.Sample. The data reported here draws on the first year data collection: a sample comprising two pieces of writing, narrative, and argument, drawn from pupils in year 8 (aged 1213) and year 10 (aged 1415). The writing sample was stratified by age, gender, and writing quality.Methods. The writing was subject to linguistic analysis at both sentence and text level, using purpose-built coding frames and a qualitative analysis sheet.Results. The linguistic analysis indicates that the patterns of linguistic development show that the influences of oral speech characteristics are strongest in weaker writing than good writing.Conclusions. Cognitive research into the translation from thought to text needs to address more explicitly the fact that good writing requires not only production of text, but also shaping of text. Although, it is well-understood that learning to be a writer draws on 'talk knowledge', this study makes it clear that one key element in learning to write with accomplishment is, in part at least, learning how not to write the way you talk, or rather acquiring adeptness in transforming oral structures into written structures.