U+0298 Latin Letter Bilabial Click

The Wikipedia has the following information about this codepoint:

The bilabial clicks are a family of click consonants that sound like a smack of the lips. They are found as phonemes only in the small Tuu language family (currently two languages, one down to its last speaker), in the ǂ’Amkoe language of Botswana (also moribund), and in the extinct Damin ritual jargon of Australia. However, bilabial clicks are found paralinguistically for a kiss in various languages, including integrated into a greeting in the Hadza language of Tanzania, and as allophones of labial–velar stops in some West African languages (Ladefoged 1968), as of /mw/ in some of the languages neighboring Shona, such as Ndau and Tonga.

The symbol in the International Phonetic Alphabet that represents the place of articulation of these sounds is ⟨ʘ⟩. This may be combined with a second letter to indicate the manner of articulation, though this is commonly omitted for tenuis clicks. An uncommon non-IPA phonetic symbol for bilabial clicks is a turned b with hook, ⟨ɋ ⟩.

In official IPA transcription, the click letter is combined with a ⟨k ɡ ŋ q ɢ ɴ⟩ via a tie bar, though ⟨k⟩ is frequently omitted. Many authors instead use a superscript ⟨k ɡ ŋ q ɢ ɴ⟩ without the tie bar, again often neglecting the ⟨k⟩. Either letter, whether baseline or superscript, is usually placed before the click letter, but may come after when the release of the velar or uvular occlusion is audible. A third convention is the click letter with diacritics for voicelessness, voicing and nasalization; it does not distinguish velar from uvular labial clicks. Common labial clicks are:

The last is what is heard in the sound sample at right, as non-native speakers tend to glottalize clicks to avoid nasalizing them.

Damin also had an egressive bilabial [ʘ↑], which may be an egressive click (if it is not buccal) and which is always followed by another consonant ([ɲ], [ŋ] or [pj]).