Studies of spoken language reveal that language change and variation is the norm. However, our understanding of language change and variation in signed languages remains limited (Lucas et al. 2010). My corpus-based studies of language variation and change explore evidence of structural patterns that demonstrate the gradual, historical changes that have shaped signed language grammar. Frequency of use is found to be a significant contributor driving language evolution in spoken languages. Similarly, from a foundation in usage-based approaches, I theorize that the more frequently a word or phrase is used in a signed language, the more it leads to structural changes in form, meaning, and function over time. Specifically, I explore in the studies described below how linguistic structures in ASL become re-structured over time and the possible factors contributing to language change and variation.