Western Dagbani, also known as 

Tomosili (or Tomosili), is a major dialect of the Dagbani language, primarily spoken in and around the administrative capital of the Northern Region of Ghana, Tamale. 

Overview

• Language Family: Dagbani is a Mabia (Gur) language, belonging to the Oti-Volta subfamily of the Niger-Congo language family.
• Speakers: There are approximately two million speakers of Dagbani in total, predominantly in Northern Ghana, with the Tomosili dialect being widely used in the region’s capital.
• Mutual Intelligibility: The Tomosili dialect is mutually intelligible with the other main dialects: Eastern Dagbani (Nayahali), centered on the traditional capital Yendi, and Nanuni (or Nanunli), spoken around Bimbilla.
• Official Orthography: While “Dagbani” is the spelling used in the official orthography to refer to the language as a whole, the Western dialect form is “Dagbanli”. 

Dialectal Differences

Differences between the Tomosili and Nayahali dialects are mainly at the phonological, lexical, and morphosyntactic levels, but they are minor enough that speakers can generally understand each other. Key variations include: 

• Vowels: Differences in root vowels in some words, as well as the frequency of certain vowel harmonies (Tomosili uses [+ATR] harmony more frequently than the other dialects).
• Lexicon: Some variations in specific vocabulary, particularly for local flora.
• Pronunciation: Alternative pronunciations of some nouns and phonetic differences in consonants, such as variations between [z] and [ʤ] or [ʔ] and [h] in different dialects. 

Many linguistic studies and analyses of Dagbani grammar and phonology are based specifically on the Tomosili dialect