What is "Lombard Effect"?

Lombard Effect

The Lombard Effect is an involuntary vocal response by speakers to the presence of background noise, in which a person’s voice is raised in response to an increase in the noise amplitude.

Today, the Lombard Effect has proven important for the study of acoustic communication in noise.

Etienne Lombard (1869–1920), was a French otolaryngologist and surgeon who discovered the noise-dependent regulation of speech amplitude, which has since carried his name.