Northeastern Vietnamese

Northeastern Vietnamese (Vietnamese: 方語東北, Bin'am: Fïëng Ngḯh Dong Bák), sometimes referred to as Dieu (㗂趙; Śiéng Dieu) is the variety of spoken in Daidieu. Nearly 100% of the population of Daidieu speaks Northeastern Vietnamese natively.

Although it is also spoken by the, it differs from other varieties spoken in , particularly in the writing system and to a lesser extent, phonology. Northeastern Vietnamese pronounciations were standarized by the Kingdom of Vietnam in the late 1940s and 1950s in dictionaries and are more conservative than other varieties. Written Vietnamese in Daidieu continues to use (Chinese characters) and  in contrast to Vietnam, where the  (chữ Quốc ngữ) is used. Despite this, Northeastern Vietnamese and other varieties remain mutually intelligible with each other.

History
Northeastern Vietnamese emerged as a separate dialect from other dialects of Vietnamese in the late 1940s. Prior to the standarization of Northeastern Vietnamese as a dialect, the North, North-Central, and Central Vietnamese dialects were mainly spoken.

Cúk Hiạ́w, other members of the PIV, and several linguists advocated for a "hyper-Sinicization" of Vietnamese in order to purge any colonial influences. Some of those reforms included eliminating all French loanwords, and reviving the use of Chữ Nôm to write Vietnamese. In 1948, the Rime Dictionary of the Vietnamese Language (韻書㗂越) was published. It standarized the pronounciations of Vietnamese and it was inspired by. The pronounciations were derived from Northern, North-Central, and Central Vietnamese.

After the end of the, Northeastern Vietnamese quickly spread across all classes of society since the government of Daidieu banned the use of the Latin script and textbooks were massively published by the government.

Phonology
The phonology of Northeastern Vietnamese tends to be more conservative than other dialects. It was standarized in the Rime Dictionary of the Vietnamese Language

Consonants

 * {| class=wikitable style=text-align:center

! colspan=2| ! Labial ! Dental/ Alveolar ! Retroflex ! Palatal ! Velar ! Glottal ! colspan=2| Nasal ! rowspan=3| Stop ! tenuis ! aspirated ! implosive ! rowspan=2| Fricative ! voiceless ! voiced ! colspan=2| Approximant ! colspan=2| Rhotic
 * colspan=2|
 * }
 * }
 * }
 * }
 * }

Comparison with other Vietnamese dialects
This uses the Vietnamese alphabet for consistency.
 * s is pronounced /ʂ/, like in all dialects except for Hanoi, which pronounces it as /s/.
 * ch is pronounced /c/, like in all dialects except for Hanoi, where it is merged with tr to become /tɕ/.
 * tr is pronounced /ʈ/, like in all dialects except for Hanoi, wheee it is merged with ch to become /tɕ/
 * Northeastern Vietnamese retains a 3-way distinction between d /z/, gi /j/, and r /r/. Those have merged into /z/ in Northern Vietnamese, while southern dialects pronounce r as /r/ and d and gi as /j/.
 * kh is pronounced /kʰ/, unlike other dialects, which pronounce it as /x/.