Sign language reveals the hidden logical structure, and limitations, of spoken language

November 6, 2018 by James Devitt, New York University
Credit: CC0 Public Domain

Sign languages can help reveal hidden aspects of the logical structure of spoken language, but they also highlight its limitations because speech lacks the rich iconic resources that sign language uses on top of its sophisticated grammar.

The study, published in Theoretical Linguistics with nine peer-commentaries, is the culmination of more than eight years of research on French Sign Language and American Sign Language (ASL) by Philippe Schlenker, a senior researcher at Institut Jean-Nicod within France's National Center for Scientific Research (CNRS) and a Global Distinguished Professor at New York University.

Sign languages are considered by linguists as full-fledged and grammatically very sophisticated languages, which are essential to the communication of Deaf people. But they also have unique insights to offer on how meaning works in language in general. In several cases, they make visible a logical structure that must be inferred indirectly in spoken language.

For instance, the logical structure of the English sentence Sarkozy told Obama that he would be elected is conveyed more transparently in sign language. The English sentence is ambiguous, Schlenker explains, as he can refer to Sarkozy or to Obama. Linguists have postulated that this is because the sentence contains some unpronounced—but cognitively real— logical variables like x and y.

If the sentence is understood as Sarkozyx told Obamay that hex would be elected, with the same variable x on Sarkozy and on he, the pronoun refers to Sarkozy; if instead he carries the variable y (= hey), it refers to Obama. Remarkably, in sign language the variables x and y can be visibly realized by positions in space, e.g. by signing Sarkozy on the left and Obama on the right. The pronoun he is realized by index pointing. If it points towards the left, it refers to Sarkozy; if it points towards the right, it refers to Obama: left and right are the visible realization of the unpronounced variables x and y.

But sign languages don't just reveal the hidden logical structure of spoken language: they also highlight some of its limitations. While some spoken words can be iconically modulated to resemble what they refer to (think of the word looooooong to mean 'very long'), this is a rare occurrence.

"By contrast, iconic modulations are entirely common in sign language," Schlenker observes. He points to the ASL verb for 'grow' (as in my group has been growing), which may be signed with broader endpoints to denote a larger growth, and may realized more quickly to represent a quicker growth.

"One and the same expression may simultaneously be logical and iconic, as is the case with pronouns," adds Schlenker, who has previously published work co-authored with Deaf consultants and researchers. "If referring to a very tall individual standing, one can point upwards because the head of the person is high; but if the tall person is hanging upside down, one will point downwards instead: the logical variable has a dual life as a simplified picture of the person it denotes."

"Along some dimensions, sign languages are more expressive than spoken because they combine the same kind of logical resources with far richer iconic means," he concludes. "They are, in a sense, 'super languages' - and they have a unique contribution to make to our understanding of human meaning."

Explore further: What does music mean? Sign language may offer an answer, new research concludes

More information: Philippe Schlenker, Visible Meaning: Sign language and the foundations of semantics, Theoretical Linguistics (2018). DOI: 10.1515/tl-2018-0012

Related Stories

Sign languages help us understand the nature of metaphors

December 10, 2010

A recent study of the use of metaphors in spoken language and various sign languages shows that certain types of metaphors are difficult to convey in sign language. The study, "Iconicity and metaphor: Constraints on metaphorical ...

Language by mouth and by hand

April 3, 2013

Humans favor speech as the primary means of linguistic communication. Spoken languages are so common many think language and speech are one and the same. But the prevalence of sign languages suggests otherwise. Not only can ...

Early exposure to language for deaf children

June 5, 2012

(Medical Xpress) -- Most agree that the earlier you expose a child to a language, the easier it is for that child to pick it up. The same rules apply for deaf children.

Recommended for you

Preventing chemical weapons as sciences converge

November 15, 2018

Alarming examples of the dangers from chemical weapons have been seen recently in the use of industrial chemicals and the nerve agent sarin against civilians in Syria, and in the targeted assassination operations using VX ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.