Applying Phonetics. Murray J. Munro

Figure 1.1 Classification of communication types

      A second dimension of communication—shown on the vertical dimension of Figure 1.1—concerns whether or not a vocal tract is involved. Across animal species, many forms of non‐vocal communication are possible. Some of these appear to be simple, as when a dog leaves its signature by urinating on a fire hydrant or a cat rubs the side of its head against a piece of furniture, leaving a scent marking. These signs are primitive in that they transmit relatively little information (“I've been here!”) and are not directed at any particular receiver. Other examples of non‐vocal communication, however, are information‐rich and geared to a specific, interested audience. Bees perform an elaborate “dance” in view of the other members of their hive, using a sophisticated non‐vocal system that informs the community of both the location and the quality of a food source, and does so with a high degree of precision.

      Human non‐vocal communication varies in its complexity as well. A gentle touch with a hand can be understood as an affectionate act, and facial expressions can reveal a wide range of emotional states. More impressively, human non‐vocal behavior is sometimes linguistic. This is because human language has more than one means of transmission or MODALITY. The vocal modality is the one we call speech, but the written modality is used for books, computer documents, emails, and text messages. While the written and vocal modalities have a great deal in common, they also differ in important respects. For instance, when we talk, we usually don't use the same level of formality and the same vocabulary as we do when writing a business memorandum. And when we write, we are not able to take advantage of certain aspects of spoken language that affect how our ideas are conveyed, such as changes in tempo, loudness, or pitch.

      In addition to the vocal and written forms of language, another modality is gesture, a means by which well over 100 distinct languages, including American Sign Language (ASL ), Japanese Sign Language (Nihon Suhwa), and Spanish Sign Language (Lengua de Signos Española), are transmitted. Sign systems are exceptional among human languages in that they do not use sound at all; however, they are every bit as complex and nuanced as spoken languages.

      Tetrapods are creatures that evolved from four‐footed ancestors. Note that tetrapods themselves do not necessarily have four feet. In fact, snakes and birds are tetrapods because their evolutionary predecessors were four‐footed reptiles. And all mammals, including humans, are tetrapods as well.

      Vocal communication, shown in the middle row of Figure 1.1, entails the production of sound using parts of the body that are also used for breathing and eating. While many animals, including humans, can vocalize, not all their sounds fall into this category. Crickets chirp or stridulate by rubbing parts of their wings against each other, and humming birds hum because of rapid movements of their wings. But virtually all tetrapods have a LARYNX, a structure in the upper part of the body that serves a variety of purposes and happens to make vocalization possible. The meow of a cat, the bleating of a goat, and even the hissing of a snake are all the result of exploiting laryngeal structures, together with other parts of the VOCAL TRACT, to create non‐linguistic sounds. When a baby screams out in frustration because it is hungry, it is communicating vocally but non‐linguistically; so too are adults when they sigh, gasp, or clear their throats to attract attention.

Speech, however, is more complicated than these non‐linguistic sounds because it is an expression of what we consider true language. But how do we define language? Doing so in a succinct way has turned out to be extremely difficult, so linguists have sometimes preferred to focus on certain properties, termed design features by Charles F. Hockett, which, taken together, might capture the difference between language and other communicative systems (Hockett & Hockett, 1960). While we won't go into all of his original 13 features here, four of them that are especially relevant to speech are ARBITRARINESS, DISCRETENESS, PRODUCTIVITY, and DUALITY OF PATTERNING. Human speech is arbitrary in the sense that there is generally no connection between the things that are referred to and the spoken symbols used to represent them, as is true for the words tree (/tɹi/), moon (/mun/), and love (/lʌv/). A non‐English‐speaker hearing these words for the first time would not be able to guess their meanings from the way they sound. In fact, two different languages sometimes assign the same sequence of sounds to entirely different meanings. For instance, the Japanese word for tree happens to be /ki/, pronounced like the English word key.

      Discreteness refers to our interpretation of the speech signal as a sequence of individual segments, which makes it possible to structure words and other linguistic units in terms of smaller chunks. These PHONES are familiar to us as vowels and consonants, and they occur in every language. Next, productivity accounts for our ability to arrange these phones in countless different orders to convey distinct meanings. A simple example is our ability to analyze the word cat as a series of three phones represented as /k/, /æ/, and /t/ in the INTERNATIONAL PHONETIC ALPHABET. Note that we can arrange the same sounds in two other orders that have distinct meanings:

      The last of the four features, duality of patterning, is closely related to discreteness and productivity and refers to the way spoken languages make use of a system of sounds that relate to a system of meanings. While the individual phones of a language are typically meaningless on their own, they can be combined in orderly ways for communicative purposes. When we say that they work as a system, we mean that within a particular language there are restrictions on how they can be combined. In English, for instance, we can't have */tkæ/, */ætk/, or any other words starting or ending with /tk/. However, we can use an additional property of our language to systematically change meanings: we add /s/ to cat, tack, and act to create the plural form of each. The four phones we've mentioned occur in thousands of other words. In fact, the remarkable consequences of discreteness, productivity, and duality of patterning become clear when we realize that English has only about 35–38 phones (depending