Sign language in the context of Finland-Swedish Sign Language

Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether unintentional or failed transmissions are included and whether communication not only transmits meaning but also creates it. Models of communication are simplified overviews of its main components and their interactions. Many models include the idea that a source uses a coding system to express information in the form of a message. The message is sent through a channel to a receiver who has to decode it to understand it. The main field of inquiry investigating communication is called communication studies.

A common way to classify communication is by whether information is exchanged between humans, members of other species, or non-living entities such as computers. For human communication, a central contrast is between verbal and non-verbal communication. Verbal communication involves the exchange of messages in linguistic form, including spoken and written messages as well as sign language. Non-verbal communication happens without the use of a linguistic system, for example, using body language, touch, and facial expressions. Another distinction is between interpersonal communication, which happens between distinct persons, and intrapersonal communication, which is communication with oneself. Communicative competence is the ability to communicate well and applies to the skills of formulating messages and understanding them.

A natural language or ordinary language is any spoken language or signed language used organically in a human community, first emerging without conscious premeditation and subject to: replication across generations of people in the community, regional expansion or contraction, and gradual internal and structural changes. The vast majority of languages in the world are natural languages. As a category, natural language includes both standard dialects (ones with high social prestige) as well as nonstandard or vernacular dialects. Even an official language with a regulating academy such as Standard French, overseen by the Académie Française, is still classified as a natural language (e.g. in the field of natural language processing), as its prescriptive aspects do not make it regulated enough to be considered a constructed or controlled natural language. Linguists broadly consider writing to be a static visual representation of a particular natural language, though, in many cases in highly literate modern societies, writing itself can also be considered natural language.

Excluded from the definition of natural language are: artificial and constructed languages, such as those developed for works of fiction; languages of formal logic, such as those in computer programming; and non-human communication systems in nature, such as whale vocalizations or honey bees' waggle dance. The academic consensus is that particular key features prevent animal communication systems from being classified as languages at all. Certain human communication or linguistic systems with no native speakers, as sometimes used in cross-cultural contexts, are also not natural languages.

In linguistics, transcription is the systematic representation of spoken language in written form. The source can either be utterances (speech or sign language) or preexisting text in another writing system.

Transcription should not be confused with translation, which means representing the meaning of text from a source-language in a target language, (e.g. Los Angeles (from source-language Spanish) means The Angels in the target language English); or with transliteration, which means representing the spelling of a text from one script to another.

Linguistics is the scientific study of language. The areas of linguistic analysis are syntax (rules governing the structure of sentences), semantics (meaning), morphology (structure of words), phonetics (speech sounds and equivalent gestures in sign languages), phonology (the abstract sound system of a particular language, and analogous systems of sign languages), and pragmatics (how the context of use contributes to meaning). Subdisciplines such as biolinguistics (the study of the biological variables and evolution of language) and psycholinguistics (the study of psychological factors in human language) bridge many of these divisions.

Linguistics encompasses many branches and subfields that span both theoretical and practical applications. Theoretical linguistics is concerned with understanding the universal and fundamental nature of language and developing a general theoretical framework for describing it. Applied linguistics seeks to utilize the scientific findings of the study of language for practical purposes, such as developing methods of improving language education and literacy.

A phoneme (/ˈfoʊniːm/) is any set of similar speech sounds that are perceptually regarded by the speakers of a language as a single basic sound—a smallest possible phonetic unit—that helps distinguish one word from another. All languages contain phonemes (or the spatial-gestural equivalent in sign languages), and all spoken languages include both consonant and vowel phonemes. Phonemes are studied under phonology, a branch of the discipline of linguistics (a field encompassing language, writing, speech and related matters).

Phonemes are often represented, when written, as a glyph (a character) enclosed within two forward-sloping slashes /. So, for example, /k/ represents the phoneme or sound used in the beginning of the English language word cat (as opposed to, say, the /b/ of bat).

A gesture is a form of nonverbal communication or non-vocal communication in which visible bodily actions communicate particular messages, either in place of, or in conjunction with, speech. Gestures include movement of the hands, face, or other parts of the body. Gestures differ from physical non-verbal communication that does not communicate specific messages, such as purely expressive displays, proxemics, or displays of joint attention. Gestures allow individuals to communicate a variety of feelings and thoughts, from contempt and hostility to approval and affection, often together with body language in addition to words when they speak. Gesticulation and speech work independently of each other, but join to provide emphasis and meaning.

Gesture processing takes place in areas of the brain such as Broca's and Wernicke's areas, which are used by speech and sign language. In fact, language is thought by some scholars to have evolved in Homo sapiens from an earlier system consisting of manual gestures. The theory that language evolved from manual gestures, termed Gestural Theory, dates back to the work of 18th-century philosopher and priest Abbé de Condillac, and has been revived by contemporary anthropologist Gordon W. Hewes, in 1973, as part of a discussion on the origin of language.

Body language is a type of nonverbal communication in which physical behaviors, as opposed to words, are used to express or convey information. Such behavior includes facial expressions, body posture, gestures, eye movement, touch and the use of space. Although body language is an important part of communication, most of it happens without conscious awareness. In social communication, body language often complements verbal communication. Nonverbal communication has a significant impact on doctor-patient relationships, as it affects how open patients are with their doctor.

As an unstructured, ungrammatical, and broadly-interpreted form of communication, body language is not a form of language. It differs from sign languages, which are true languages with complex grammar systems and exhibiting the fundamental properties considered to exist in all languages.

In linguistics, a compound is a lexeme (less precisely, a word or sign) that consists of more than one stem. Compounding, composition or nominal composition is the process of word formation that creates compound lexemes. Compounding occurs when two or more words or signs are joined to make a longer word or sign. Consequently, a compound is a unit composed of more than one stem, forming words or signs. If the joining of the words or signs is orthographically represented with a hyphen, the result is a hyphenated compound (e.g., must-have, hunter-gatherer). If they are joined without an intervening space, it is a closed compound (e.g., footpath, blackbird). If they are joined with a space (e.g. school bus, high school, lowest common denominator), then the result – at least in English – may be an open compound.

The meaning of the compound may be similar to or different from the meaning of its components in isolation. The component stems of a compound may be of the same part of speech—as in the case of the English word footpath, composed of the two nouns foot and path—or they may belong to different parts of speech, as in the case of the English word blackbird, composed of the adjective black and the noun bird. With very few exceptions, English compound words are stressed on their first component stem.

Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (which does not exist in every language) between translating (a written text) and interpreting (oral or signed communication between users of different languages); under this distinction, translation can begin only after the appearance of writing within a language community.

A translator always risks inadvertently introducing source-language words, grammar, or syntax into the target-language rendering. On the other hand, such "spill-overs" have sometimes imported useful source-language calques and loanwords that have enriched target languages.

Interpreting is translation from a spoken or signed language into another language, usually in real time to facilitate live communication. It is distinguished from the translation of a written text, which can be more deliberative and make use of external resources and tools.

The most common two modes of interpreting are simultaneous interpreting, which is performed contemporaneously with the expression of the source language, and consecutive interpreting, where the interpreted speech is heard only during associated breaks in the original speech.

The number of languages natively spoken in Africa is variously estimated (depending on the delineation of language vs. dialect) at between 1,250 and 2,100, and by some counts at over 3,000. Nigeria alone has over 500 languages (according to SIL Ethnologue), one of the greatest concentrations of linguistic diversity in the world. The languages of Africa belong to many distinct language families, among which the largest are:

• Niger–Congo, which include the large Atlantic-Congo and Bantu branches in West, Central, Southeast and Southern Africa.
• Afroasiatic languages are spread throughout Western Asia, North Africa, the Horn of Africa and parts of the Sahel.
• Saharan, Nilotic and Central Sudanic languages (grouped under the hypothetical Nilo-Saharan macro-family), are present in East Africa and Sahel.
• Austronesian languages are spoken in Madagascar and parts of the Comoros.
• Khoe–Kwadi languages are spoken mostly in Namibia and Botswana.
• Indo-European languages, while not indigenous to Africa, are spoken in South Africa and Namibia (Afrikaans, English, German) and are used as lingua francas in Liberia and the former colonies of the United Kingdom (English), former colonies of France and of Belgium (French), former colonies of Portugal (Portuguese), former colonies of Italy (Italian), former colonies of Spain (Spanish) and the current Spanish territories of Ceuta, Melilla and the Canary Islands and the current French territories of Mayotte and La Réunion.

There are several other small families and language isolates, as well as creoles and languages that have yet to be classified. In addition, Africa has a wide variety of sign languages, many of which are language isolates.

Phonetics is a branch of linguistics that studies how humans produce and perceive sounds or, in the case of sign languages, the equivalent aspects of sign. Linguists who specialize in studying the physical properties of speech are phoneticians. The field of phonetics is traditionally divided into three sub-disciplines: articulatory phonetics, acoustic phonetics, and auditory phonetics. Traditionally, the minimal linguistic unit of phonetics is the phone—a speech sound in a language which differs from the phonological unit of phoneme; the phoneme is an abstract categorization of phones and it is also defined as the smallest unit that discerns meaning between sounds in any given language.

Phonetics deals with two aspects of human speech: production (the ways humans make sounds) and perception (the way speech is understood). The communicative modality of a language describes the method by which a language produces and perceives languages. Languages with oral-aural modalities such as English produce speech orally and perceive speech aurally (using the ears). Sign languages, such as Australian Sign Language (Auslan) and American Sign Language (ASL), have a manual-visual modality, producing speech manually (using the hands) and perceiving speech visually. ASL and some other sign languages have in addition a manual-manual dialect for use in tactile signing by deafblind speakers where signs are produced with the hands and perceived with the hands as well.

Phonology (formerly also phonemics or phonematics) is the branch of linguistics that studies how languages systematically organize their phonemes or, for sign languages, their constituent parts of signs. The term can also refer specifically to the sound or sign system of a particular language variety. At one time, the study of phonology related only to the study of the systems of phonemes in spoken languages, but now it may relate to any linguistic analysis either:

Sign languages have a phonological system equivalent to the system of sounds in spoken languages. The building blocks of signs are specifications for movement, location, and handshape. At first, a separate terminology was used for the study of sign phonology ("chereme" instead of "phoneme", etc.), but the concepts are now considered to apply universally to all human languages.

A talking animal or speaking animal is any non-human animal that can produce sounds or gestures resembling those of a human language. Several species or groups of animals have developed forms of communication which superficially resemble verbal language, however, these usually are not considered a language because they lack one or more of the defining characteristics, e.g. grammar, syntax, recursion, and displacement. Researchers have been successful in teaching some animals to make gestures similar to sign language, although whether this should be considered a language has been disputed.

The origin of speech differs from the origin of language because language is not necessarily spoken; it could equally be written or signed. Speech is a fundamental aspect of human communication and plays a vital role in the everyday lives of humans. It allows them to convey thoughts, emotions, and ideas, and providing the ability to connect with others and shape collective reality.

Many attempts have been made to explain scientifically how speech emerged in humans, although to date no theory has generated agreement.

A vocabulary (also known as a lexicon) is a set of words, typically the set in a language or the set known to an individual. The word vocabulary originated from the Latin vocabulum, meaning "a word, name". It forms an essential component of language and communication, helping convey thoughts, ideas, emotions, and information. Vocabulary can be oral, written, or signed and can be categorized into two main types: active vocabulary (words one uses regularly) and passive vocabulary (words one recognizes but does not use often). An individual's vocabulary continually evolves through various methods, including direct instruction, independent reading, and natural language exposure, but it can also shrink due to forgetting, trauma, or disease. Furthermore, vocabulary is a significant focus of study across various disciplines, like linguistics, education, psychology, and artificial intelligence. Vocabulary is not limited to single words; it also encompasses multi-word units known as collocations, idioms, and other types of phraseology. Acquiring an adequate vocabulary is one of the largest challenges in learning a second language.