information (n.)

LINGUISTICS has made several uses of this fundamental concept, both in a general sense, and also as formalized in statistical terms, derived from the mathematical theory of COMMUNICATION. Ideas derived from information theory (as formulated originally by Claude Shannon and Warren Weaver in their book The Mathematical Theory of Communication (1949)) have been applied in PHONETICS (e.g. in analyzing the amount of information carried by the various features of the sound wave), GRAMMAR (e.g. in studies of the predictability of various parts of a SENTENCE) and SEMANTICS (e.g. in applying the notion of ‘choice’ between alternatives in the analysis of semantic CONTRASTS, as in DYNAMIC semantics). The concept of REDUNDANCY, for example, ultimately derives from this approach.

In its general sense, the term is used by several linguists as a basis for a theoretical account of the STRUCTURE of messages. It is postulated that speech can be seen as displaying an information structure, encoding the relative salience of the elements in a message, with formally identifiable units of information. INTONATION provides the main signal for such UNITS. The TONE UNIT represents an information unit, and the NUCLEAR tone marks the information FOCUS. Many sentences will be single units of information, e.g. the box on the table is ready for pòsting/, but altering the intonation, in this view, alters the number of information units, e.g. the box on the táble/ is ready for pòsting/. Even if one tone unit is retained, altering the TONICITY will change the information structure, e.g. the bòx on the table is ready for posting/ (i.e. not the envelope). The further analysis of information structure is complex and controversial: a common next step is to distinguish between GIVEN and NEW information. Analysts who use this approach (e.g. HALLIDAYAN linguists) usually distinguish between information structure and THEMATIC and grammatical structure.