fossilized (adj.)

A term used in GRAMMAR and LEXICOLOGY to refer to a type of CONSTRUCTION which is no longer PRODUCTIVE in a LANGUAGE. In English, for example, fossilized SENTENCES include So be it, Long live the Queen and Least said, soonest mended; fossilized LEXICAL items include such REDUPLICATIVE forms as goody-goody, hocus-pocus, and several types of IDIOM.

In the acquisition of a foreign language, the stabilization of a level of achievement in the use of a linguistic form which falls short of the norms of the target language. No further learning takes place, and the form becomes a fossilized error in the usage of the learner, part of the learner’s INTERLANGUAGE.