A quantitative analysis of sign lengthening in American Sign Language

In spoken languages, disfluent speech, narrative effects, discourse information, and phrase position may influence the lengthening of segments beyond their typical duration. In sign languages, however, the primary use of the visual-gestural modality results in articulatory differences not expressed in spoken languages. This paper looks at sign lengthening in American Sign Language (ASL). Comparing two retellings of the Pear Story narrative from five signers, three primary lengthening mechanisms were identified: elongation, repetition, and deceleration. These mechanisms allow signers to incorporate lengthening into signs which may benefit from decelerated language production due to high information load or complex articulatory processes. Using a mixed effects model, significant differences in duration were found between (i) non-conventionalized forms vs. lexical signs, (ii) signs produced during role shift vs. non-role shift, (iii) signs in phrase-final/initial vs. phrase-medial position, (iv) new vs. given information, and (v) (non-disordered) disfluent signing vs. non-disfluent signing. These results provide insights into duration effects caused by information load and articulatory processes in ASL.