This project wants to contribute to a better understanding of the grammar underlying Spanish-English codeswitching phenomena. In concrete, it looks into the factors governing an overlooked but highly productive construction in codeswitching contexts, namely mitigation structures. These express quantitative or qualitative reduction of a base form, as in a little casa or the casita (‘the small house’). The construction is very differently represented in both English and Spanish: Spanish has a highly productive synthetic diminutive system that can construct forms of various grammatical categories through a large inventory of affixes (e.g.-ito, -illo), while English is considered to be a language that does not have many diminutive affixes but mostly turns to analytical lexical items (e.g. little). In a Spanish-English codeswitching context, bilingual speakers depend on both grammatical systems to express mitigation. Despite its common occurrence and varied forms, no research has been done as yet on the use, form and function of mitigation in this particular context. Through a comparative quantitative and qualitative analysis of mitigation instantiations in two bilingual communities (Miami and El Paso), it is aimed to expose any grammatical system underlying to (Spanish-English) codeswitching. The project adopts a multimethod approach and combines corpus research with an experimental design.