(near) Open/low front unrounded vowelThis is the vowel used in English “sad”. 

(near) Open/low front unrounded vowel

This is the vowel used in English “sad”.  It exists as an allophone of other vowels in Turkish, Russian, Dutch, Slovak, Swedish and French (as a nasal vowel). 

Phonemically, it exists in English, all Arabic languages/dialects, all Berber languages, Somali, Afrikaans, Norwegian, Finnish, Estonian, Latvian, Lithuanian, Danish, Kurdish, Azeri, Persian, Qazaq, Uzbek, Turkmen, Uyghur, Bashkir, Orya, Sinhalese, and in some dialects of Portuguese, Andalusian Spanish, Greek, Romanian.