Structure preservation

Definition
Structure preservation is a property of (lexical) rules which entails that they cannot introduce segments which are not otherwise motivated as underlying phonological segments of the language.

Syntax
A rule or rule system is structure preserving if its output is independently available as an underlying (underived) structure. The hypothesis that natural language grammars are structure preserving has first been elaborated in Emonds (1970), and is taken for granted in much ongoing work.

Example
The underlying sound inventory of Dutch does not contain voiceless sonorants, but it does contain voiced and voiceless obstruents. Furthermore, Dutch has a rule of final devoicing, but characteristically this rule does not effect sonorants. Hence, the rule of final devoicing is structure preserving.

Links

 * Utrecht Lexicon of Linguistics