Distinctive vowel length was inherited from late Proto-Slavic, with some changes (for example, stressed acute and circumflex vowels, and some long vowels occurring after the stress, were shortened). Additional vowel lengths were introduced in Proto-Polish (as in other West Slavic languages) as a result of compensatory lengthening when a yer in the next syllable disappeared. If a yer (or other vowel) disappeared, the preceding vowel became long (unless it was also a yer, in which case it became a short "e").