We question the commonly accepted assumption that American Sign Language (ASL) has no overt copula. We present evidence that one of the functions of the sign self in present-day ASL is as a copula. This sign evolved into its current function by way of a grammaticalization process called the ‘copula cycle’ (Katz 1996). The copula cycle consists of a deictic item transforming into a demonstrative pronoun and then into a copula by means of a series of syntactic reanalyses. We present corpus evidence from Old French Sign Language (LSF) in the 1850s, Old ASL in the 1910s, and present-day ASL dating to the 2000s and the late 2010s, and with these data analyze ASL examples of syntactic structures outlined by Li and Thompson (1977) that led to the increased use of self as a copula. We also find that self, which is not generally regarded as a pointing sign, follows the grammaticalization scheme for pointing signs outlined by Pfau and Steinbach (2006), indicating that the scheme may be used for signs that are derived from demonstratives. Ultimately, we conclude that ASL undergoes the same grammaticalization processes as spoken languages.
grammaticalization, copula, copula cycle, corpus linguistics, historical linguistics, American Sign Language