This article aims at examining some linguistic dysfunctions of Creole pupils of La Reunion, via the categories of gender and number, in the particular linguistic context of diglossia. The postulate rests on the idea that variety in spelling errors hides a certain regularity. Our hypothesis tends to show that three prominent features underly the visible instability of errors: regularity, differentiation and standardization. Therefore, one expects to see a double movement of simplification and of complexification, that shows either in the absence of discrimination, or in some form of assimilation, adaptation or fixation. Dysfunctions concerning grammatical morphograms will illustrate our analysis. Finally the didactic perspectives in order to remedy these phenomena will be addressed.