Alignment Mouth Demonstrations in Sign Languages

Nonmanual articulations in sign languages range from being semantically impoverished to semantically rich, and from being independent of manual articulations to coordinated with them. But, while this range has been well noted, certain nonmanuals remain understudied. Of particular interest to us are nonmanual articulations coordinated with manual articulations, which, when considered in conjunction with those manual articulations, are semantically rich. In which ways can such different articulators coordinate and what is the linguistic effect or purpose of such coordination?

Of the nonmanual articulators, the mouth is articulatorily the most versatile. We therefore examined mouth articulations in a single narrative told in the sign languages of America, Brazil, and Germany. We observed optional articulations of the corners of the lips that align with manual articulations spatially and temporally in classifier constructions. The lips, thus, enhance the message by giving redundant information, which should be particularly useful in narratives for children. Examination of a single children's narrative told in these same three sign languages plus six other sign languages yielded examples of one type of these optional alignment articulations, confirming our expectations. Our findings are coherent with linguistic findings regarding phonological enhancement and overspecification.