Centuries of linguistic research has stated that phonological change is inescapable. Some have claimed syntax to be inert, changing only due to phonological or semantic change. This project takes an unusual and challenging view: Phonology is pertinacious and changes in existing phonological systems are governed by two principles of Pertinacity.

Either a particular phonological pattern persists but is extended to apply to new forms and different outputs emerge: [A] same pattern, different outputs.

Or output forms look alike, but the underlying phonological system alters due to changes elsewhere in the grammar: [B] different pattern, same outputs.

The principle of Pertinacity allows us to elucidate the expectations and to understand the reasons behind the issues of the whys and why nots of phonological change.

DISTINCTIVENESS of the proposal: Setting it apart from more narrowly departmentalised specialist approaches, classical historical research will be combined with psycho- and neurolinguistic experimentation and computational speech recognition to shed light from different angles on central issues of linguistic change and stability, diversity and uniformity.

To examine the principle of Pertinacity, we will investigate similar internal phonological processes and external loans via contact, across 3 language families (West & North Germanic, Indo-Aryan).

A. THEORETICAL: DIACHRONIC & SYNCHRONIC ANALYSES
internal: Determine the extent to which comparable phonological processes lead to different phonological contrasts in related languages
external: Determine the effect of adaptation of similar loans on grammars of related languages
B. PSYCHOLINGUISTIC & NEUROLINGUISTIC EXPERIMENTATION
language processing: Investigate experimentally to what extent similar underlying patterns with differential outputs govern phonological processing in related languages
C. COMPUTER SPEECH RECOGNITION
Simulate the effect of different representations with our Flexible Speech Recognition system (FlexSR)