As the "minimal" vowel of Israeli Hebrew, e is the vowel most likely to break unpronounceable consonant clusters, and to be affected by casual vowel deletion. Both e-insertion and casual deletion are automatic, which suggests that e may be characterized as phonetically unmarked. In contrast, a is the most prominent vowel in Israeli Hebrew. It has the highest sonority, is the least marked phoneme in the five-vowel system, and is the most frequent vowel in the language by far. Consequently, c functions as the default choice in acronym formation, which is a conscious, non-automatic process. It is thus the natural, most expected vowel of Israeli Hebrew from a phonological point of view that is not automatic-phonetic, but rather "psychologically-based." Its status and frequency have at least one important application to the teaching of reading to beginners and to vowel marking in glossaries and dictionaries.