constant (adj.)

A type of OPPOSITION recognized in PRAGUE SCHOOL PHONOLOGY, distinguished from NEUTRALIZABLE. A constant opposition exists when all its members can occur in all possible positions, e.g. wherever /p/ might be found in a LANGUAGE, a contrast with /b/ will also be found. A DISTINCTION such as English /t/ v. /d/, however, is neutralizable because, in some positions, the CONTRAST disappears (as in /t/ following INITIAL /s/).