The city of Sanandaj is at the southeastern periphery of the area of spoken modern Aramaic languages. Its geography makes the Neo-Aramaic of Sanandaj quite distinct from other dialects. Two different colloquial Aramaic dialects developed in Sanandaj: Jewish Hulaula and Christian Senaya. The two languages developed along different lines, so that the two are not mutually comprehensible. One distinctive difference between the two is the sound change associated with the Middle Aramaic fricative θ (th), often rendered as l in Hulaula, and s in Senaya. For example, mîθa, 'dead', is mîsa in Senaya, and mîla in Hulaula.
Most Senaya speakers are members of the Chaldean Catholic Church, which broke away from the Church of the East in the 16th century and entered into communion with the Roman Catholic Church. However, Senaya is incomprehensible to speakers of Chaldean Neo-Aramaic, also Chaldean Catholics, originally from Iraq because of the heavy Kurdish influences on the language. In the middle of the 20th century, the Chaldean Bishop of Senna (as Sanandaj is called in Senaya) was moved to Tehran. The Christian community soon followed, so that there are no native speakers of Senaya left in Sanandaj. In Tehran, Senaya has been heavily influenced by the Urmežnāya dialect of Assyrian Neo-Aramaic spoken by the larger Church of the East community there. Both church communities use classical Syriac in worship. Senaya is written in the Madnhāyâ version of the Syriac alphabet, which is also used for classical Syriac.