Voiceless labiodental stop

The voiceless labiodental stop is a consonant sound produced like a [p], but with the lower lip contacting the upper teeth, as in [f]. This can be represented in the IPA as ⟨p̪⟩. A separate symbol not recognized by the IPA that is often seen, especially in Bantu linguistics, is the qp ligature ⟨ȹ⟩.

The voiceless labiodental stop is possibly not phonemic in any language, though see the entry on Shubi. However, it does occur allophonically. The XiNkuna dialect of Tsonga has affricates, [p̪͡f] and [b̪͡v] (that is, [ȹ͡f] and [ȸ͡v]), which unlike the bilabial-labiodental affricate [p͡f] of German, are purely labiodental.

One reason that this sound may be so rare is that a person with uneven upper teeth, or gaps between the teeth, will not be able to completely block the flow of air out of the mouth, and therefore will tend to produce a fricative [f] rather than a stop [p̪].