The Khalkha dialect ( / Halh ayalguu /, ) is a dialect of central Mongolic widely spoken in Mongolia. According to some classifications, the Khalkha dialect includes Inner Mongolian varieties such as Shiliin gol, Ulaanchab and Sönid. As it was the basis for the Cyrillic orthography of Mongolian, it is de facto the national language of Mongolia. The name of the dialect is related to the name of the Khalkha Mongols and the Khalkha river. There are certain differences between normative (standardised form of Khalkha) and spoken Khalkha. For example, the normative language uses proximal demonstratives based on the word stem (except for the nominative and the accusative which takes the stem ) and thus exhibits the same developmental tendency as exhibited by Oirat. On the other hand, the spoken language also makes use of paradigms that are based on the stems and. This seems to agree with the use in Chakhar Mongolian. The same holds for the distal demonstrative. Khalkha may roughly be divided into Northern and Southern Khalkha, which would include Sönid etc. Both varieties share affricate depalatalization, namely, > and > except before *i, while Southern Khalkha patterns with Chakhar and Ordos Mongolian in that it exhibits a dissimilating deaspiration; e.g. >. However, Mongolian scholars more often hold that the border between Khalkha and Chakhar is the border between the Mongolian state and the Chakhar area of Inner Mongolia of China. Especially in the speech of younger speakers, (or ) > may take place, as in Written Mongolian qabtasu > Sünid ~ 'cover (of a book)'. One of the classifications of Khalkha dialect in Mongolia divides it into 3 subdialects: Central, Western and Eastern. The orthography of the Mongolian Cyrillic alphabet is essentially based on the Central Khalkha dialect. Among the main differences is the pronunciation of initial letter х in feminine words which is in Central Khalkha pronounced as it is written, in Western Khalkha as h, and in Eastern Khalkha as g; e.g. хөтөл hötöl (Central Khalkha), көтөл kötöl (Western Khalkha), гөтөл götöl (Eastern Khalkha). The initial letter х is pronounced in masculine words in Western Khalkha as (almost not heard) if the following consonant is voiceless, and is pronounced as (and devoiced to ) in Eastern Khalkha; e.g. хутга hutga (Central Khalkha), hутага hutaga (Western Khalkha), гутага gutaga (Eastern Khalkha). Initial /tʰ/ is unaspirated in Eastern Khalkha; e.g. талх talh (Central Khalkha), талқ talq (Western Khalkha), dalh (Eastern Khalkha).

Grouping of Khalkha dialects

In Juha Janhunen's book Mongolian, he groups the Khalkha dialects into the following 19: