The influence of acoustics on speech production: A noise-induced stress phenomenon known as the Lombard reflex

Recently, a number of researchers reported quantitative results about the acoustic changes between normal and Lombard speech, These results highlighted that the nature of the Lombard reflex is highly speaker-dependent. In this paper, after briefly discussing the influence of acoustics on speech production, we summarize some important characteristics of the Lombard reflex. Then, we review some experimental results showing how the Lombard reflex varies with the speaker gender, the language, and the environment (type of noise). Finally, we briefly discuss the use of relational features as a way to reduce the influence of the Lombard reflex on automatic speech recognizers.