Kirundi is mutually intelligible with Kinyarwanda, the national language of Rwanda, and the two form parts of the wider dialect continuum known as Rwanda-Rundi.

[3] Kirundi is natively spoken by the Hutu, including Bakiga and other related ethnicities, as well as Tutsi, Twa and Hima among others have adopted the language.

[8] Rundi is often used in phonology to illustrate examples of Meeussen's rule[9][10] In addition, it has been proposed that tones can shift by a metrical or rhythmic structure.

It has been proposed that sequences that are CVV in the surface realization are actually CV in the underlying deep structure, with the consonant coalescing with the first vowel.

In accordance with the constitution, many Burundian government orders, especially those printed in the Bulletin Officiel du Burundi from 1962 to 1963, were written in both French and Kirundi.