The Proto-Slavic nasal vowels "ǫ" and "ę" were denasalized in the 10th century. The nasal vowel "ǫ" was replaced by "u" and "ú", i.e. "zǫbъ > zub" (a tooth), "lǫka > lúka" (a meadow) probably through an extinct nasal vowel "ų": "ǫ > ų > u/ú". The denasalization of "ę" was similar: "ę > ą̈ > ä/a̋". These forms from the 11th-12th centuries have been preserved in some Slovak dialects until the modern age (Orava, Gemer and Sotak dialects). The central Slovak dialects preserved only the short form "ä". In other dialects, they changed to wide range of monophthongs and diphthongs.