Chad has two official languages, Arabic and French, and Ethnologue reports over 120 indigenous languages in the country. Due to governmental bilingualism, inter-ethnic marriages, and language contact, most Chadians are multilingual.

The co-official languages of Chad, French and Arabic, reflect Chad's complex sociolinguistic history where indigenous people and languages coexist with two different waves of colonization.

Arabic took hold following 16th century Arab migrations from Sudan, Nubia, and possibly through Trans-Saharan trade routes. A vernacular version of Arabic, Chadian Arabic, is a lingua franca and the language of commerce, spoken by approximately 60% of the population.

France gained control of Chad during the early 20th century, and their colonial policies focused on spreading French as the primary language in Chad. A 1924 letter from the governor general of French Chad declared: "The spread of French is a necessity [...] The native is only allowed to present his/her requests in French." After Chad gained independence in 1960, French was retained by the new government as the official language, in part because it functioned as a neutral choice, rather than having to elevate one indigenous language over another.

Arabic joined French as a co-official language in 1978, as part of a deal ending the Chadian Civil War by increasing northern Chadians' role in government. French remains the dominant language in many workplaces, schools, and administrative institutions. A 2022 analysis found that about 75% of administrative institutions spoke exclusively in French, and a further 20% spoke French and Arabic.

The language with the most first-language speakers in Chad is likely Ngambay, which has an estimated one million speakers. Ngambay is used as a commercial and inter-ethnic bridge language in Southern Chad and in the capital, N'Djamena.

Many of major indigenous languages of Chad are members of the Sara-Bongo-Bagirmi language branch of the proposed Nilo-Saharan language family. In addition to Ngambay, these include Kaba, Deme, Lutos, and Barma/Bagirmi. These languages are mostly used in southern Chad and some of them extend into neighboring countries, especially Cameroon or the Central African Republic.

In parts of Southern Chad, the linguistic landscape is highly diverse. It is a border region between three language families: Niger-Congo, Nilo-Saharan, and Afro-Asiatic, plus a language isolate, Laal. A 2025 study in two villages along the Chari River found that every villager spoke at least three languages fluently, and most spoke at least four. As a result, even though many of the languages have a small number of speakers, they are relatively vibrant, continuing to get passed down through the generations.