Cardinal vowels

Reference vowels used to describe the sounds of languages X-rays of Daniel Jones' [i, u, a, ɑ]. Highest tongue positions of cardinal front and back vowels Diagram of relative highest points of tongue for cardinal vowels The cardinal vowel quadrilateral, a more commonly seen schematic diagram of highest tongue positions of cardinal vowels Cardinal vowels (sometimes abbreviated as CVs) are a set of reference vowels used by phoneticians in describing the sounds of languages. They are classified depending on the position of the tongue relative to the roof of the mouth, how far forward or back is the highest point of the tongue, and the position of the lips (rounded or unrounded). A cardinal vowel is a vowel sound produced when the tongue is in an extreme position, either front or back, high or low. The current system was formulated by Daniel Jones in the early 20th century, though the idea goes back to earlier phoneticians, notably Alexander John Ellis and Alexander Melville Bell. Description Definitions Four of the cardinal vowels—[i, a, ɑ, u]—have articulatory definitions as fixed reference points: [i] is produced with the tongue as close as possible to the hard palate without