Towards a definition and working model of stress and its effects on speech

Discussions at the ESCA-NATO Workshop on Speech Under Stress (Lisbon, Portugal, September 1995) centred on definitions and models of stress and its effects. Based on the Workshop discussions, in this paper we attempt to produce a definition of stress, and propose a number of stress models which clarify issues in this field, and which might be adopted by the speech community. The concept of stress is very broad and used differently in a number of domains - a definition of stress has thus remained elusive. Similarly, our understanding of the processes of stress and the ways in which it affects speech is incomplete, and any models used to describe stress are somewhat elementary. Greater separation of stressors (the causes of stress) and strain (the effects of stress) is proposed, and methods for relating stressors to strains are presented. Suggestions for future research directions in this field are also made.