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When Sign Language Influences Speech

The case of a manual language influencing a spoken language

Post written by François Grosjean.

Have you ever spoken with people who know sign language, such as American Sign Language (ASL), or who are learning it (see here)? Have you noticed how their hands move much more than they would normally? It happened to me a lot when I was learning to sign and then conducting research on the language.

San Diego State University researchers Shannon Casey, Karen Emmorey and Heather Larrabee set about studying the influence of ASL as a second language on the gestures (also called co-speech gestures) that are used when English is being spoken.

They asked English speakers, acquiring ASL, to re-tell in English two scenes of a Tweety and Sylvester cartoon. The students did this twice, in the same experimental conditions, once when they started their ASL acquisition and then again one year later, after six hours of instruction per week covering three 10-week quarters.

What they found is that the ASL learners, when speaking English, had increased their rate of gestures significantly after one year of language instruction, in particular iconic gestures, i.e. gestures that represent the attributes, actions, or relationships of objects or characters, according to University of Chicago Professor David McNeill. An example would be making a downward movement with the hands to represent a bowling ball being thrown down a pipe (as in the Tweety and Sylvester cartoon). The authors also observed a significant increase of marked ASL handshapes (such as the L handshape illustrating this post) after one year of ASL.

Interestingly, students were aware of these changes in their gesturing. In another study done by the same authors, 75% of the students at the end of two semesters of ASL instruction felt that their co-speech gestures had indeed increased since they had started learning ASL. Practically the same percentage (76%) felt that their gestures had changed in some way during that time. According to them, they were bigger and used more space, as is the case when using sign language. They also felt that they used more gestures to express emotion or to explain what they were saying.

The authors of the study propose several reasons for this change in number and type of gestures. Since signing involves manual articulators, the students may have become accustomed to moving their hands when communicating, and this carries over into monolingual speech environments.

Another reason they put forward is that learners of ASL become accustomed to signing and speaking at the same time when using sign language, that is they produce a sign and whisper its English translation equivalent. This behavior, which is true of many hearing people who sign, not just learners, simply carries over into speech. Finally, a third possibility could be that the students' repertoire of conventional gestures (akin to crossing your fingers for "good luck") may simply have been increased by bringing in new gestures. The problem, of course, is that these new gestures are not meaningful to people who do not know sign language.

Whatever the reason, signing definitely influences gesturing in speech. Two questions come to mind though: Would a difference have been found in number and type of gestures if the students had retold the cartoons to English monolinguals, on the one hand, and to English-ASL bilinguals, on the other? We would expect this to be the case (see here). And how long does this influence last when a person stops signing for good, as in my case regretfully?

Photo courtesy of Mario Carneiro, Wikimedia Commons.


Casey, S., Emmorey, K. and Larrabee, H. (2012). The effects of learning American Sign Language on co-speech gesture. Bilingualism: Language and Cognition, 15(4), 677-686.

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