Speech recognition in adverse conditions: A review

Abstract

This article presents a review of the effects of adverse conditions (ACs) on the perceptual, linguistic, cognitive, and neurophysiological mechanisms underlying speech recognition. The review starts with a classification of ACs based on their origin: Degradation at the source (production of a noncanonical signal), degradation during signal transmission (interfering signal or medium-induced impoverishment of the target signal), receiver limitations (peripheral, linguistic, cognitive). This is followed by a parallel, yet orthogonal classification of ACs based on the locus of their effect: Perceptual processes, mental representations, attention, and memory functions. We then review the added value that ACs provide for theories of speech recognition, with a focus on fundamental themes in psycholinguistics: Content and format of lexical representations, time-course of lexical access, word segmentation, feed-back in speech perception and recognition, lexical-semantic integration, interface between the speech system and general cognition, neuroanatomical organisation of speech processing. We conclude by advocating an approach to speech recognition that includes rather than neutralises complex listening environments and individual differences.

Keywords:

• Speech recognition
• Lexical access
• Adverse conditions
• Signal degradation
• Cognitive load
• Masking

Acknowledgments

This article and the organisation of this special issue were made possible thanks to support from: The Leverhulme Trust (F/00 182/BG), the ESRC (RES-062-23-2746), the Marie Curie Foundation (MRTN-CT-2006-035561), the Experimental Psychology Society (EPS), the Wellcome Trust (WT090961AIA), and the MRC (MHD: MC_US_A060_0038).

Notes

¹Our review of ACs in speech recognition does not directly address short-term cues to segment-level features. For some data and discussion of cue re-weighting for segment identification in noise, see, e.g., Parikh and Loizou (2005), Jiang, Chen, and Alwan (2006); see also Assmann and Summerfield (2004) for a review).