|Speech & Language|
Human speech is the vocalized form of human communication. Though speech is a dominant form of human communication, it is by no means the only form. In fact, normal speech is often supplemented by auditory signals such as Morse code or train whistles, by visual exchanges such as signing and gesturing, or with tactile information such as braille. Under abnormal conditions such as deafness, speech may be absent altogether and in cases such as Helen Keller, concomitant loss of vision may necessitate extraordinary communication methods involving other senses combined with great effort, assistance, and dedication.
The two components of vocal communication by humans, speech production and speech perception, link human thoughts to the outside world, including especially the written word but also other communication technologies. As noted in the Ohio State University's Language Files, "Spoken language encodes thought into a physically transmittable form, and writing in turn encodes spoken language into a physically preservable form." Not all human languages have a corresponding written form, but those that do give great insight into reasons for the human success as a species.
Speech and language arguably comprise the greatest communication technologies of all time. But exactly what is speech? How is it different from the audio communications by animals? How did it come about in the first place and how or why does it change over time? Like other adaptations of living things, does it appear and flourish, and then die off? Why are some languages disappearing though others are flourishing? And what exactly is the relationship of speech to language?
Normal human speech is produced from air provided by the lungs which creates sounds in the glottis in the larynx. These sounds are modified by the vocal tract to form different vowels (open vocal tract) and consonants (constricted vocal tract). Among
most languages have voiced vowels in which the vocal chords are vibrating, but unvoiced vowels
for the Native American languages Cheyenne and Totonac.
As for consonants, these can involve a sudden release of air (stops or plosives), rapid vibration (fricatives), or other variants and they may be voiced or unvoiced.
A given language is a collection of characteristic sounds called phonemes. By contrast, an alphabet is a corresponding set of written symbols for the language. An example of an English phoneme representation is shown above for the sentence "Writing preserves speech."
One or two symbols may represent a single English phoneme. Moreover,
in some languages including English, one letter of the alphabet (e.g., p as in park, phone) may map to different sounds. Other languages where there is a 1:1 correspondence between sounds and letters are generally makes them easier to learn.
Several pioneering books about human language appeared in the early 20th century, including two entitled simply Language by Edward Sapir (1921) and Leonard Bloomfield (1933). Bloomfield presented a comprehensive description of American structural linguistics based on scientific structure called Bloomfieldian and
paved the way for American linguist Charles Francis Hockett (1916-2000) who developed many influential ideas in American structural linguistics. Hockett's phase of structuralism is often referred to as Distributionalism or Taxonomic structuralism and is most often referenced in discussions of his list of language characteristics listed below and discussed as length in his book (1966, The Problem of Universals in Language.
Each of these features is found in every known human language
but each seems to be lacking in at least one known animal communicative system. Therefore, they do not constitute a defining list for languages, human or otherwise.
Hockett's Language Features
Writing is the visual representation of speech.
In general, a language is also easier to learn if it has an alphabet, which may be a phonographic system (symbols represent sounds, as in English) or a morphographic system (symbols represent words, as in traditional Chinese morphographs). The 4 Chinese symbols below represent the English phrase "dances with wolves" ("with wolves together dance"),
Most (>75%) languages have a word order preference; Subject-Object-Verb (SOV, e.g., Hopi, Lakota) is the most common type and Subject-Verb-Object (SVO, e.g., English, Polish, Russian) is less common. The definition of all acceptable sentences for a language is known as its grammar (sometimes called its syntax).
In SVO languages the subject tends to be the most important word in a sentence and can often stand by itself as a grammatically correct sentence. English examples are:
In SOV languages the verb tends to be the most important word in a sentence and can often stand by itself as a grammatically correct sentence. Lakota examples are:
A grammar is expressed as a series of rules or productions. A sample grammar for the English sentences might begin with such rules as:
To find out whether a sentence is well-formed, a candidate string must first be scanned for tokens (sometimes called lexemes). The English sentence above ('Bill studied English') has 3 tokens: 'Bill', 'studied', and 'English' and discovering these in an arbitrary string of characters is usually called lexical analysis. Typically the tokens are fed one-at-a-time into a parser that uses the language grammar rules to determine whether or not the string is well-formed. Note that in the English example the tokens are easy to delimit - white space separates them, but this is not usually the case, as the Lakota example above illustrates. Given lists of tokens and grammar rules, two long-standing computer programs - LEX and YACC - can be used to generate the required lexical analyzer and parser. FLEX and BISON are popular free versions of these two traditional tools that in addition to their analytical use in human speech are also now help computers and other devices synthesize and recognize speech and primitive language features.
Many studies aimed at primate recognition and understanding of human speech have demonstrated primitive communication capability. These studies shed light on the origin of language and are summarized online at Primate Use of Language and highlight Washoe, the chimpanzee who was taught to sign by her caretakers, Allen and Beatrice Gardner; Koko, the female gorilla proficient in American Sign Language; and the Orang Utan Language Project, where four magificent primates are learning to communicate in a language designed especially for them at the National Zoo. For an interesting lesson on human-bonobo communication, catch the YouTube video on the famed pink rabbit.
Like many other forms of communication, human language is little more than an agreed-upon protocol between sender and receiver and not a very permanent one at that. For one thing, human language seems tied to the Forkhead box protein P2, encoded in the SPCH1 locus of human chromosome 7. Mutations there are now associated with various speech and language disorders as discussed here, and some scientists believe mutations in the same locus gave humans several advantages for speech, perhaps around only 50,000 years ago. Given the rapid advances in genome sequencing over the last several years, it seems likely that much new knowledge of the human to non-human language relationships will emerge soon, pointing to relationships among various human cultures as well.