It is spoken in Botswana and Namibia by about 4,000 people.
!Xóõ belongs to the Southern African branch of the Khoisan language phylum. It is categorized in the Southern subbranch of the Southern African Khoisan languages. Its closest relative is =/Hua.
There are about 80 clicks in it, with 5 basic clicks and 17 or so accompaniments, including the rare uvular closure as opposed to the velar closure of most clicks. The five basic clicks are the bilabial, the dental, the alveolar, the palatal, and the lateral click. Clicks fall into two main classes depending on the sound made by the burst when they are articulated: clicks with abrupt, short bursts and those with long, high-frequency bursts.
The click accompaniments are described in this quote: "!Xoo...actually has *more* click accompaniments than plain dorsals, /kh, k, g, k', kx', gkh, gkx' (the last two are prevoiced stops), qh, q, G, q', Gqh/ vs clicks /k|h, k|, g|, k|x, k|x', gk|x, gk|x', q|h, q|, G|, q|', gq|h, Gq|h, N|, N_o|, 'N|, N_o|'/. ! Xoo also has a large set of clicks, labial, dental, alveolar, palatal, and lateral."
Vowels can vary in a number of ways, including pharyngealization and strident voice. Strident and pharyngealized vowels are distinguished in !Xóõ, with the strident ones being both phonologically pharyngealized and breathy-voiced. !Xóõ is a tonal language and the ó in !Xóõ is high tone.
!Xóõ is a Subject Verb Object language. It is prepositional, and genitives, adjectives, relative clauses and even numbers come after the nouns to which they apply. Reduplication is used to form causatives. Much like most Indo-European languages, !Xóõ always puts the question word at the beginning of the sentence.
The linguist Anthony Traill has done extensive research into this language.