Usage-based linguistics postulates that multi-word expressions constitute a substantial part of language structure and use, and are formed through repeated chunking and stored as exemplar wholes. They are also re-used to produce new sequences by means of schematization. While there is extensive research on multi-word expressions in many spoken languages, little is known about the status of multi-word expressions in the mainstream U.S. variety of American Sign Language. This paper investigates recurring multi-word expressions, or sequences of multiple signs, that involve (...) a high-frequency sign of visual perception glossed as look and the family of ‘look’ signs. The look sign exhibits two broad functions: look/‘vision’ references literal or metaphorical vision and look/‘reaction’ signals a person’s reaction to a visual stimulus. Data analysis reveals that there are recurring sequences in distinct syntactic environments associated with the two functions of look, suggesting that look is in the process of grammaticalization from a verb of visual perception to a stance verb. The sequences demonstrate the emergence of linguistic structure from repeated use through the domain-general cognitive process of chunking in ASL. (shrink)