In this study, we examine the use of grammatical vocabulary by pupils (in the fourth grade at a French secondary school) during interviews about helping procedures and metagraphic representations for writing in French. The vocabulary in use comes from academic grammar, and its density and relevance are highly variable. Surprisingly, some words that have been in use since primary school are mastered by only a few students. Thus, only 76.2% of the occurrences are relevant for the word adjective, only 58.3% for pronoun and 51.4% for determiner. We created correlation tests in order to assess the function of grammatical vocabulary in spelling analysis by students. We tested the link between spelling success and three variables: the diversity of relevant grammatical words, the number of substitution procedures, and the number of syntactical analyses. All correlations were positive and significant, but syntactic analyses were more strongly correlated to spelling success. The use of grammatical vocabulary doesn’t appear to be essential, as some pupils spell correctly without it, but we noticed that all pupils using relevant vocabulary made some mistakes. Therefore, the results validate the interest of using a precise grammar vocabulary in support of syntactic analyzes to develop spelling performance.