Sign phonetics is the study of how sign languages are produced and perceived, by native as well as by non-native signers. Most research on sign phonetics has focused on American Sign Language (ASL), but there are many different sign languages around the world, and several of these, including British Sign Language, Taiwan Sign Language, and Sign Language of the Netherlands, have been studied at the level of phonetics. Sign phonetics research can focus on individual lexical signs or on the movements of the nonmanual articulators that accompany those signs. The production and perception of a sign language can be influenced by phrase structure, linguistic register, the signer’s linguistic background, the visual perception mechanism, the anatomy and physiology of the hands and arms, and many other factors. What sets sign phonetics apart from the phonetics of spoken languages is that the two language modalities use different mechanisms of production and perception, which could in turn result in structural differences between modalities. Most studies of sign phonetics have been based on careful analyses of video data. Some studies have collected kinematic limb movement data during signing and carried out quantitative analyses of sign production related to, for example, signing rate, phonetic environment, or phrase position. Similarly, studies of sign perception have recorded participants’ ability to identify and discriminate signs, depending, for example, on slight variations in the signs’ forms or differences in the participants’ language background. Most sign phonetics research is quantitative and lab-based.
The term “philosophy of language” is intrinsically paradoxical: it denominates the main philosophical current of the 20th century but is devoid of any univocal definition. While the emergence of this current was based on the idea that philosophical questions were only language problems that could be elucidated through a logico-linguistic analysis, the interest in this approach gave rise to philosophical theories that, although having points of convergence for some of them, developed very different philosophical conceptions. The only constant in all these theories is the recognition that this current of thought originated in the work of Gottlob Frege (b. 1848–d. 1925), thus marking what was to be called “the linguistic turn.” Despite the theoretical diversity within the philosophy of language, the history of this current can however be traced in four stages: The first one began in 1892 with Frege’s paper “Über Sinn und Bedeutung” and aimed to clarify language by using the rules of logic. The Fregean principle underpinning this program was that we must banish psychological considerations from linguistic analysis in order to avoid associating the meaning of words with mental pictures or states. The work of Frege, Bertrand Russell (1872–1970), George Moore (1873–1958), Ludwig Wittgenstein (1921), Rudolf Carnap (1891–1970), and Willard Van Orman Quine (1908–2000) is representative of this period. In this logicist point of view, the questions raised mainly concerned syntax and semantics, since the goal was to define a formalism able to represent the structure of propositions and to explain how language can describe the world by mirroring it. The problem specific to this period was therefore the function of representing the world by language, thus placing at the heart of the philosophical debate the notions of reference, meaning, and truth. The second phase of the philosophy of language was adumbrated in the 1930s with the courses given by Wittgenstein (1889–1951) in Cambridge (The Blue and Brown Books), but it did not really take off until 1950–1960 with the work of Peter Strawson (1919–2006), Wittgenstein (1953), John Austin (1911–1960), and John Searle (1932–). In spite of the very different approaches developed by these theorists, the two main ideas that characterized this period were: one, that only the examination of natural (also called “ordinary”) language can give access to an understanding of how language functions, and two, that the specificity of this language resides in its ability to perform actions. It was therefore no longer a question of analyzing language in logical terms, but rather of considering it in itself, by examining the meaning of statements as they are used in given contexts. In this perspective, the pivotal concepts explored by philosophers became those of (situated) meaning, felicity conditions, use, and context. The beginning of the 1970s initiated the third phase of this movement by orienting research toward two quite distinct directions. The first, resulting from the work on proper names, natural-kind words, and indexicals undertaken by the logician philosophers Saul Kripke (1940–), David Lewis (1941–2001), Hilary Putnam (1926–2016), and David Kaplan (1933–), brought credibility to the semantics of possible worlds. The second, conducted by Paul Grice (1913–1988) on human communicational rationality, harked back to the psychologism dismissed by Frege and conceived of the functioning of language as highly dependent on a theory of mind. The focus was then put on the inferences that the different protagonists in a linguistic exchange construct from the recognition of hidden intentions in the discourse of others. In this perspective, the concepts of implicitness, relevance, and cognitive efficiency became central and required involving a greater number of contextual parameters to account for them. In the wake of this research, many theorists turned to the philosophy of mind as evidenced in the late 1980s by the work on relevance by Dan Sperber (1942–) and Deirdre Wilson (1941–). The contemporary period, marked by the thinking of Robert Brandom (1950–) and Charles Travis (1943–), is illustrated by its orientation toward a radical contextualism and the return of inferentialism that draws strongly on Frege. Within these theoretical frameworks, the notions of truth and reference no longer fall within the field of semantics but rather of pragmatics. The emphasis is placed on the commitment that the speakers make when they speak, as well as on their responsibility with respect to their utterances.