The Features of Human
(adapted from Hockett, Charles. 1960. The Origin of Speech.)
Hockett isolated 13 features that characterize human language and which distinguish it from other communication systems. The following diagram graphically represents each of the thirteen features. Each feature is numbered and listed below the diagram, along with a more developed discussion of the feature.
1. Vocal-auditory channel -- This means that the standard human language occurs as a vocal (making sounds with the mouth) type of communication which is perceived by hearing it. There are obvious exceptions: writing and sign language are examples of communication in the manual-visual channel. However, the vast majority of human languages occur in the vocal-auditory channel as their basic mode of expression. Writing is a secondary, and somewhat marginal form of language, while sign languages are in limited use, mostly among deaf people who are limited in their ability to use the auditory part of the vocal-auditory channel.
2. Broadcast transmission and directional reception -- This means that the human language signal is sent out in all directions, while it is perceived in a limited direction. For spoken language, the sound perpetuates as a waveform that expands from the point of origin (the mouth) in all directions. This is why a person can stand in the middle of a room and be heard by everyone (assuming they are speaking loudly enough). However, the listener hears the sound as coming from a particular direction and is notably better at hearing sounds that are coming from in front of the them than from behind them.
3. Rapid fading (Transitoriness) -- This means that the human language signal does not persist over time. Speech waveforms fade rapidly and cannot be heard after they fade. This is why it is not possible to simply say "hello" and have someone hear it hours later. Writing and audio-recordings can be used to record human language so that it can be recreated at a later time, either by reading the written form, or by playing the audio-record.
4. Interchangeability -- This means that the speaker can both rreceive and broadcast the same signal. This is distinctive from some animal communications such as that of the stickle fish. The stickle fish make auditory signals based on gender (basically, the males say "I'm a boy" and the females say "I'm a girl"). However, male fish cannot say "I'm a girl," although they can perceive it. Thus, stickle fish signals are not interchangeable.
5. Total feedback -- this means that the speaker can hear themselves speak and can monitor their language performance as they go. This differs from some other simple communication systems, such as traffic signals. Traffic signs are not normally capable of monitor their own functions (a red light can't tell when the bulb is burned out, i.e.).
6. Specialization -- This means that the organs used for producing speech are specially adapted to that task. The human lips, tongue, throat, etc. have been specialized into speech apparati instead of being merely the eating apparati they are in many other animals. Dogs, for example, are not physically capable of all of the speech sounds that humans produce, because they lack the necessary specialized organs.
7. Semanticity -- This means that specific signals can be matched with specific meanings. This is a fundamental aspect of all communication systems. For example, in French, the word sel means a white, crystalline substance consisting of sodium and chlorine atoms. The same substance is matched with the English word salt. Anyone speaker of these languages will recognize that the signal sel or salt refers to the substance sodium chloride.
8. Arbitrariness -- This means that there is no necessary connection between the form of the signal and the thing being referred to. For example, something as large as a whale can be referred to by a very short word. Similarly, there is no reason that a four-legged domestic canine should be called a dog and not a chien or a perro or an anjing (all words for 'dog' in other languages). Onomatopoeic words such as "meow" or "bark" are often cited as counter-examples, based on the argument that they are pronounced like the sound they refer to. However, the similarity if very loose (a dog that actually said "bark" would be very surprising) and does not always hold up across languages (Spanish dogs, for example, say "guau"). So, even onomatopoeic words are, to some extent, arbitrary.
9. Discreteness -- This means that the basic units of speech (such as sounds) can be categorized as belonging to distinct categories. There is no gradual, continuous shading from one sound to another in the linguistics system, although there may be a continuum in the real physical world. Thus speakers will perceive a sound as either a [p] or a [b], but not as blend, even if physically it falls somewhere between the two sounds.
10. Displacement -- This means that the speaker can talk about things which are not present, either spatially or temporally. For example, human language allows speakers to talk about the past and the future, as well as the present. Speakers can also talk about things that are physically distant (such as other countries, the moon, etc.). They can even refer to things and events that do not actually exist (they are not present in reality) such as the Easter Bunny, the Earth having an emperor, or the destruction of Tara in Gone with the Wind.
11. Productivity -- This means that human languages allow speakers to create novel, never-before-heard utterances that others can understand. For example, the sentence "The little men who live in my socks-drawer told me that Evis will come back from Mars on the 10th and will set all the politicians of India right." is a novel and never-heard-before sentence (at least, I hope it is!), but any fluent speaker of English would be able to understand it (and realize that the speaker was not completely sane, at least for his noble wish).
12. Traditional Transmission -- This means that human language is not something inborn. Although humans are probably born with an ability to do language, they must learn, or acquire, their native language from other speakers. This is different from many animal communication systems where the animal is born knowing their entire system, e.g. bees are born knowing how to dance and some birds are born knowing their species of bird-songs (this is not true of all birds).
13. Duality of patterning -- This means that the discrete parts of a language can be recombined in a systematic way to create new forms. This idea is similar to Productivity (Feature 11). However, Productivity refers to the ability to generate novel meanings, while Duality of patterning refers to the ability to recombine small units in different orders.