It has become traditional to locate cardinal vowels on a four-sided figure (quadrilateral) of the shape seen in Fig. 5 (the design used here is the one recommended by the international Phonetic Association in 1989). The exact shape is not really important - a square would do quite well - but we will use the traditional shape. The vowels on Fig. 5 are the so-called primary cardinal vowels; these are the vowels that are most familiar to the speakers of most European languages, and there are other cardinal vowels that sound less familiar.