Paralanguage is a component of meta-communication that may modify meaning, give nuanced meaning, or convey emotion, by using techniques such as prosody, pitch, volume, intonation, etc. It is sometimes defined as relating to nonphonemic properties only. Paralanguage may be expressed consciously or unconsciously.
The study of paralanguage is known as paralinguistics, and was invented by George L. Trager in the 1950s, while he was working at the Foreign Service Institute of the Department of State. His colleagues at the time included Henry Lee Smith, Charles F. Hockett (working with him on using descriptive linguistics as a model for paralanguage), Edward T. Hall developing proxemics, and Ray Birdwhistell developing kinesics. Trager published his conclusions in 1958, 1960 and 1961.
His work has served as a basis for all later research, especially those investigating the relationship between paralanguage and culture (since paralanguage is learned, it differs by language and culture). A good example is the work of John J. Gumperz on language and social identity, which specifically describes paralinguistic differences between participants in intercultural interactions. The film Gumperz made for BBC in 1982, Multiracial Britain: Crosstalk, does a particularly good job of demonstrating cultural differences in paralanguage, and the impact these have on relationships.
Paralinguistic information, because it is phenomenal, belongs to the external speech signal (Ferdinand de Saussure's parole) but not to the arbitrary conventional code of language (Saussure's langue).
The paralinguistic properties of speech play an important role in human communication. There are no utterances or speech signals that lack paralinguistic properties, since speech requires the presence of a voice that can be modulated. This voice must have some properties, and all the properties of a voice as such are paralinguistic. However, the distinction linguistic vs. paralinguistic applies not only to speech but to writing and sign language as well, and it is not bound to any sensory modality. Even vocal language has some paralinguistic as well as linguistic properties that can be seen (lip reading, McGurk effect), and even felt, e.g. by the Tadoma method.
Consequently, paralinguistic cues relating to expression have a moderate effect of semantic marking. That is, a message may be made more or less coherent by adjusting its expressive presentation. For instance, upon hearing an utterance such as "I drink a glass of wine every night before I go to sleep" is coherent when made by a speaker identified as an adult, but registers a small semantic anomaly when made by a speaker identified as a child. This anomaly is significant enough to be measured through electroencephalography, as an N400. Individuals with disorders along autism spectrum have a reduced sensitivity to this and similar effects.
Emotional tone of voice, itself paralinguistic information, has been shown to affect the resolution of lexical ambiguity. Some words have homophonous partners; some of these homophones appear to have an implicit emotive quality, for instance the sad "die" contrasted with the neutral "dye"; uttering the sound /dai/ in a sad tone of voice can result in a listener writing the former word significantly more often than if the word is uttered in a neutral tone.
Some of the linguistic features of speech, in particular of its prosody, are paralinguistic or pre-linguistic in origin. A most fundamental and widespread phenomenon of this kind is described by John Ohala as the "frequency code". This code works even in communication across species. It has its origin in the fact that the acoustic frequencies in the voice of small vocalizers are high while they are low in the voice of large vocalizers. This gives rise to secondary meanings such as 'harmless', 'submissive', 'unassertive', which are naturally associated with smallness, while meanings such as 'dangerous', 'dominant', and 'assertive' are associated with largeness. In most languages, the frequency code also serves the purpose of distinguishing questions from statements. It is universally reflected in expressive variation, and it is reasonable to assume that it has phylogenetically given rise to the sexual dimorphism that lies behind the large difference in pitch between average female and male adults.
In text-only communication such as email, chatrooms and instant messaging, paralinguistic elements can be displayed by emoticons, font and color choices, capitalization and the use of non-alphabetic or abstract characters. Nonetheless, paralanguage in written communication is limited in comparison with face-to-face conversation, sometimes leading to misunderstandings.
A gasp is a kind of paralinguistic respiration in the form of a sudden and sharp inhalation of air through the mouth. A gasp may indicate difficulty breathing and a panicked effort to draw air into the lungs. Gasps also occur from an emotion of surprise, shock or disgust. Like a sigh, a yawn, or a moan, a gasp is often an automatic and unintentional act. Gasping is closely related to sighing, and the inhalation characterizing a gasp induced by shock or surprise may be released as a sigh if the event causing the initial emotional reaction is determined to be less shocking or surprising than the observer first believed.
As a symptom of physiological problems, apneustic respirations (a.k.a. apneusis), are gasps related to the brain damage associated with a stroke or other trauma.
A sigh is a kind of paralinguistic respiration in the form of a deep and especially audible, single exhalation of air out of the mouth or nose, that humans use to communicate emotion. It is voiced pharyngeal fricative, sometimes associated with a guttural glottal breath exuded in a low tone. It often arises from a negative emotion, such as dismay, dissatisfaction, boredom, or futility. A sigh can also arise from positive emotions such as relief, particularly in response to some negative situation ending or being avoided. Like a gasp, a yawn, or a moan, a sigh is often an automatic and unintentional act. In literature, a sigh is often used to signify that the person producing it is lovelorn.
Scientific studies show that babies sigh after 50 to 100 breaths. This serves to improve the mechanical properties of lung tissue, and it also helps babies to develop a regular breathing rhythm. Behaviors equivalent to sighing have also been observed in animals such as dogs, monkeys, and horses.
In text messages and internet chat rooms, or in comic books, a sigh is usually represented with the word itself, 'sigh', possibly within asterisks, *sigh*.
Clearing one's throat is a metamessaging nonverbal form of communication used in announcing one's presence upon entering the room or approaching a group. It is done by individuals who perceive themselves to be of higher rank than the group they are approaching and utilize the throat-clear as a form of communicating this perception to others.
As a form of metacommunication, the throat-clear is acceptable only to signal that a formal business meeting is about to start. It is not acceptable business etiquette to clear one's throat when approaching a group on an informal basis; the basis of one's authority has already been established and requires no further reiteration by this ancillary nonverbal communication.
Mhm is between a literal language and movement, by making a noise "hmm" or "mhm", to make a pause for the conversation or as a chance to stop and think.
Observing the "mhm" act is especially used in narratives interview, by conducting biographical interview with survivor from some traumatic events such as Shoah, or sexual violence. In this kind of interview, it's better for the interviewers or counselors not to intervene too much when an interviewee is talking. Observing emotional differences and taking care of an interviewee's mental status is an important way to find slight changes during conversation.