This is known as acrophony; It is present in some modern scripts, such as Greek, and many Semitic scripts, such as Arabic, Hebrew, and Syriac.
ðɪs ɪz nˈoʊn æz ækɹˈɑːfəni; ɪɾ ɪz pɹˈɛzənt ɪn sˌʌm mˈɑːdɚn skɹˈɪpts, sˈʌtʃ ɐz ɡɹˈiːk, ænd mˈɛni sɛmˈɪɾɪk skɹˈɪpts, sˈʌtʃ ɐz ˈæɹɐbˌɪk, hˈiːbɹuː, ænd sˈɪɹiˌæk.