Writing proficiently in any language requires knowing about much more than grammar, lexis, register, genres, audience and rhetorical situation. It also requires that writers call upon implicit sociocultural and contextual inferences made via indexes. Indexes convey a wide range of sociocultural information about social background, professional and cultural identity, affective and epistemological positioning, gender and ethnicity. The ways in which this information is indexed, however, can vary significantly from one language to another, making indexicality a significant concern for international writers as they negotiate their positions through writing. This paper describes a novel method in writing research, indexical analysis, which is used to identify how French politeness norms are indexed in application letters written in English by first-language (L1) French students. It was found that although their writing was considered grammatically correct, divergences in terms of where and how politeness was expressed resulted in a negative evaluation by readers. Developing more conscious awareness of the implicit norms that organize thoughts and attitudes for both writers and readers may allow for better recognition of how indexes may differ across languages.Writing proficiently in any language requires knowing about much more than grammar, lexis, register, genres, audience and rhetorical situation. It also requires that writers call upon implicit sociocultural and contextual inferences made via indexes. Indexes convey a wide range of sociocultural information about social background, professional and cultural identity, affective and epistemological positioning, gender and ethnicity. The ways in which this information is indexed, however, can vary significantly from one language to another, making indexicality a significant concern for international writers as they negotiate their positions through writing. This paper describes a novel method in writing research, indexical analysis, which is used to describe how French politeness norms are indexed in application letters written in English by first-language (L1) French students. It was found that although the students’ writing was considered grammatically correct, divergences in terms of where and how politeness was expressed resulted in a negative evaluation by readers. Developing more conscious awareness of the implicit norms that organize thoughts and attitudes for both writers and readers may allow for better recognition of how indexes can differ across languages.