linearity (n.)

(1) A term used in LINGUISTICS to describe the characteristic REPRESENTATION of LANGUAGE as a unidimensional SEQUENCE of ELEMENTS or RULES. The assumption is made that it is possible to order rules in a sequence, and to adhere strictly to this ordering in constructing DERIVATIONS without any loss of GENERALITY (compared to an unordered set of rules or a set ordered on a different principle, e.g. one of simultaneous application). It is also claimed that linear ordering makes it possible to formulate grammatical processes that would otherwise not be expressible with complete generality.

(2) In PHONOLOGY, linearity is an organizational principle, whereby each occurrence of a PHONEME is associated with a specific sequence of PHONES (minimally, one phone) which realize that phoneme. If phoneme A precedes phoneme B, then phone(s) A′ will precede phone(s) B′. Linearity is thus one of the preconditions of BIUNIQUENESS. The principle is criticized by GENERATIVE phonologists, as part of a general attack on TAXONOMIC phonemics.

(3) A family of FAITHFULNESS CONSTRAINTS in OPTIMALITY THEORY which evaluates, along with CONTIGUITY, the degree of preservation of ADJACENCY ordering of SEGMENTS between two forms. It penalizes changes in segment ordering between the two corresponding REPRESENTATIONS. METATHESIS is an example of a phenomenon which violates linearity.