Introduction to the special issue on the phonetics of under-documented languages.

As scientists, it is important to sample as broadly as possible; however, there is a bias in the research performed on the speech acoustics of the world's languages toward work on languages of convenience (e.g., English). This special issue seeks to initiate increased publication of acoustic research on the sounds of the world's languages. The special issue contains a sample of 25 under-documented languages. While large relative to previous work (particularly in the Journal of the Acoustical Society of America), the 23 articles in this issue just scratch the surface. To have a better understanding of the fundamentals of speech communication, it is imperative, as a research community, to make a concerted effort to learn more about how speech sounds are perceived and produced in a wide variety of languages.