Bilabial vs. Labiodental: The Difference Between P and F

Two consonants that even beginning phonetics students can usually produce correctly illustrate one of the clearest distinctions in articulatory phonetics: the difference between bilabial and labiodental sounds. A bilabial consonant uses both lips together; a labiodental consonant presses the upper teeth against the lower lip. This single articulatory difference creates an entirely different acoustic output and separates phonemes that languages treat as non-interchangeable.

Bilabial Consonants

The bilabial consonants include stops /p/ (voiceless) and /b/ (voiced), the nasal /m/, the fricative /ɸ/ (voiceless, as in Japanese fu), and the approximant /w/. These sounds require both lips to meet or approach each other without teeth involvement. The stops /p/ and /b/ are among the most universally attested consonants—found in roughly 95 % of the world's languages—because the bilabial closure is a mechanically simple gesture available to every human vocal tract. Explore both symbols on the IPA Chart.

Labiodental Consonants

Labiodental consonants arise when the upper incisors make contact with the inner surface of the lower lip. The most common are /f/ (voiceless) and /v/ (voiced). Despite being familiar to speakers of European languages, labiodentals are actually uncommon globally. Many languages in sub-Saharan Africa and East Asia lack them entirely. Evolutionary linguists Patrick Dediu and Steven Moran have proposed that the spread of labiodentals correlates with the adoption of food-processing technologies that change the way teeth sit in the jaw—though this remains controversial.

The contrast matters for second-language learning: speakers of languages without /f/ and /v/ frequently substitute /p/ or /b/, creating the stereotypical accent features associated with certain language backgrounds. Compare how different language families handle this distinction using our comparison tool, or browse the sounds index for frequency data across the PHOIBLE corpus.