Another important factor in determining vowels sounds is the shape of the lips - whether they are rounded, spread or neutral. In English the front vowels. (the sounds for example, in heed, head, and hat) are unrounded while some of the back vowels (the sounds in shoe and put, for example) are rounded. It is possible to make either rounded or unrounded vowel sounds at all the front and back cardinal vowel positions. The u sound in the French word tu (meaning you) is essentially the same as the sound in the English word heed, apart from lip rounding. Both are closed/ vowels fronted (tongue at highest, most forward positions)but the English sound is with unrounded lips and the French sound is with rounded lips. According to the International Phonetic Alphabet by which phonetic transcriptions are made, different symbols are assigned to sounds which vary only in terms of lip rounding. Thus the vowel in heed is represented as [i] and the vowel in the French tu as [y].
