The `Lombard effect' consists of various speech adaptation mechanisms human speakers use involuntarily to counter influences that a noisy environment has on their speech intelligibility. These adaptations are highly dependent on the characteristics of the noise and happen rapidly. Modelling the effect for the output side of speech interfaces is therefore difficult: the noise characteristics need to be evaluated continuously and speech synthesis adaptations need to take effect immediately. This paper describes and evaluates an online system consisting of a module that analyses the acoustic environment and a module that adapts the speech parameters of an incremental speech synthesis system in a timely manner. In an evaluation with human listeners the system had a similar effect on intelligibility as had human speakers in offline studies. Furthermore, during noise the Lombard-adapted speech was rated more natural than standard speech.
Bibliographic reference. Rottschäfer, Sebastian / Buschmeier, Hendrik / Welbergen, Herwin van / Kopp, Stefan (2015): "Online Lombard adaptation in incremental speech synthesis", In INTERSPEECH-2015, 80-84.