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

The Influence of Lombard Effect on Speech Recognition

“…It was also demonstrated that the presence of auditory feedback of speech is necessary to maintain the intelligibility of Lombard speech, as the primary purpose of Lombard effect is to increase speech intelligibility in communication with other speakers in noisy environments. It was reported in (Junqua, 1996) and in (Van Summers et al, 1988) that acoustic changes that occur in speech in a noisy environment are different from person to person and are highly speaker-dependent (Junqua, 1996). This was confirmed also in (Van Summers et al, 1988), where the authors reported a significant increase in fundamental frequency for one male speaker, but not for the second, when they spoke in quiet and in different levels of noise.…”

“…The conducted research showed that Lombard speech is different from normal speech in a number of ways. The main changes of characteristics of Lombard speech can be seen in increase in voice level, fundamental frequency and vowel duration, and a shift in formant center frequencies for F1 and F2 Applebaum et al, 1996;Junqua, 1996;. It was also reported in (Hanley & Steer, 1949) that speaking rate may be reduced when speech is produced in a noisy environment.…”

“…In 1911 Etienne Lombard discovered the psychological effect of speech produced in the presence of noise (Lombard, 1911). The Lombard effect is a phenomenon in which speakers increase their vocal levels in the presence of a loud background noise and make several vocal changes in order to improve intelligibility of the speech signal Bond et al, 1989;Dreher & O'Neill, 1957;Egan, 1971;Junqua, 1996;Van Summers et al, 1988). In nowadays speech recognition applications appearance of Lombard effect can be expected in various domains, where spontaneous and conversational speech communication will take place in uncontrolled acoustic environments.…”

“…Some authors have also argued that both mechanisms may contribute to the changes made by the speaker in noisy environments (Junqua, 1993). Detailed surveys of the literature on the Lombard effect phenomenon was made in (Lane & Tranel, 1971) and more recently in (Junqua, 1996). The conducted research showed that Lombard speech is different from normal speech in a number of ways.…”

“…This was confirmed also in (Van Summers et al, 1988), where the authors reported a significant increase in fundamental frequency for one male speaker, but not for the second, when they spoke in quiet and in different levels of noise. The characteristics of Lombard speech may also vary with the type of ambient noise, and with the language of the speaker (Junqua, 1996). It was suggested in (Lane & Tranel, 1971) that the magnitude of the speakers' response to noise is likely to be governed by the desire to achieve intelligible communication.…”