The category of "English as a Second Language" or "ESL" student is no longer a label of someone in the process of learning English. Rather, linguistic categorization is a complex social processes of ascribed identity formation that positions students as deficits and others, circumscribing them out of belonging to both academic settings and a nation-state, and implicated in racialization. Research that investigates policies for multilingual students often take language-proficiency based categories like "ESL students" as an a "priori" condition, thus ignoring the key role institutional practices such as assessment and placement play in the construction of these categories. In this study I utilize Actor Network Theory (ANT) to examine assessment and placement practices through which categories and categorization of ESL and developmental students are enacted. Examining how groups and anti-groups are generated reveals that the enaction of "ESL student" is highly mediated by the local campus context, language ideologies and the perceived differences between their student populations. Assessment and placement networks are embedded in racializing processes that position and define diverse students as deficits, as not belonging, thus reinforcing raciolinguistic hierarchies.