Ultrasound tongue imaging (UTI) uses ultrasound to form images of tongues.
It has been used for speech production and linguistics research since it came into regular clinical use in the 1960s and 1970s.
[1] It is a non-invasive technique that allows researchers to view the shape, position and movements of the tongue (from root to apex) in real time during speech.
[2] UTI became popular in phonetics laboratories as ultrasound units become more portable and affordable.
[1] The Ultrafest conference assembles researchers that employ UTI.