The open back unrounded vowel, or low back unrounded vowel, is a type of vowel sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɑ⟩, and the equivalent X-SAMPA symbol is A. The letter ⟨ɑ⟩ is called script a because it lacks the extra hook on top of a printed letter a, which corresponds to a different vowel, the open front unrounded vowel. Script a, which has its linear stroke on the bottom right, should not be confused with turned script a, ɒ, which has its linear stroke on the top left and corresponds to a rounded version of this vowel, the open back rounded vowel.