ט Ṭêṯ, a pharyngealized t, , ע ʽAyin (or ʽE in some dialects), a pharyngealized glottal stop (sometimes considered to be a voiced pharyngeal approximant), or , צ Ṣāḏê, a pharyngealized s, , ק Qôp, a voiceless uvular stop, . Ancient Aramaic may have had a larger series of emphatics, and some Neo-Aramaic languages definitely do. Not all dialects of Aramaic give these consonants their historic values. Overlapping with the set of emphatics are the "guttural" consonants. They include ח Ḥêṯ and ע ʽAyn from the emphatic set, and add א ʼĀlap̄ (a glottal stop) and ה Hê (as the English "h"). Aramaic classically has a set of four sibilants (ancient Aramaic may have had six): ס, שׂ (as in English "sea"), ז (as in English "zero"), שׁ (as in English "ship"), צ (the emphatic Ṣāḏê listed above). In addition to these sets, Aramaic has the nasal consonants מ m and נ n, and the approximants ר r (usually an alveolar trill), ל l, י y and ו w. Historical sound changes Six broad features of sound change can be seen as dialect differentials: Vowel change occurs almost too frequently to document fully, but is a major distinctive feature of different dialects. Plosive/fricative pair reduction. Originally, Aramaic, like Tiberian Hebrew, had fricatives as conditioned allophones for each plosive. In the wake of vowel changes, the distinction eventually became phonemic; still later, it was often lost in certain dialects. For example, Turoyo has mostly lost , using instead, like Arabic; other dialects (for instance, standard Assyrian Neo-Aramaic) have lost and and replaced them with and , as with Modern Hebrew. In most dialects of Modern Syriac, and are realized as after a vowel. Loss of emphatics. Some dialects have replaced emphatic consonants with non-emphatic counterparts, while those spoken in the Caucasus often have glottalized rather than pharyngealized emphatics. Guttural assimilation is the main distinctive feature of Samaritan pronunciation, also found in Samaritan Hebrew: all the gutturals are reduced to a simple glottal stop. Some Modern Aramaic dialects do not pronounce h in all words (the third person masculine pronoun hu becomes ow). Proto-Semitic */θ/ */ð/ are reflected in Aramaic as */t/, */d/, whereas they became sibilants in Hebrew (the number three is שלוש šālôš in Hebrew but תלת tlāṯ in Aramaic, the word gold is זהב zahav in Hebrew but דהב dehav in Aramaic). Dental/sibilant shifts are still happening in the