The influence of first language spelling and response inhibition skills on English-as-an-additional-language spelling

English spelling is widely investigated, but little is known about spelling in English as an additional language (EAL), especially in the context of text production. This study examined the contribution of language-specific Italian and EAL spelling knowledge, and inhibition skills to EAL spelling in Italian adolescents’ essays. Fifty students, attending two language-focused high schools in Italy, completed standardized spelling tests in Italian and English, a Flanker task to assess inhibition skills, and two, persuasive texts in English. Texts were scored for spelling errors, fluency (words/minute), lexical diversity (type token ratio, TTR), and productivity (total words). Spelling errors in EAL writing were 3%. An exploratory factor analysis identified two factors accounting for EAL spelling in writing: a general EAL spelling/writing (including spelling ability, writing fluency, TTR and total words) factor, and a cognitive factor, corresponding to response inhibition skills. Italian spelling skills did not predict EAL-in-text spelling. The only significant predictors of spelling in EAL writing were EAL spelling/writing and inhibition skills. Inhibition skills contributed to explain morphological and code-switch errors, but not phonological and orthographic errors in English texts. These findings align with the contrastive typological framework and phonological and orthographic proximity hypothesis of language transfer.