Definition:
An obstruent is a consonant sound produced by significantly obstructing airflow through the vocal tract. The three main classes of obstruents are stops (complete blockage then release), fricatives (narrow constriction producing turbulence), and affricates (stop followed immediately by a fricative). Obstruents contrast with sonorants, which allow relatively free airflow.
In-Depth Explanation
The obstruent–sonorant distinction is one of the fundamental divisions in phonetics and phonology. Obstruents share key properties:
- Airflow is significantly blocked or constricted. This obstruction creates the noise energy that characterizes these sounds.
- They can be voiceless or voiced. Many languages systematically contrast voiced and voiceless obstruents: English /p/ vs. /b/, /t/ vs. /d/, /s/ vs. /z/. The voicing distinction is the primary phonemic contrast in English obstruents.
- They are [-sonorant] in feature geometry. This feature distinguishes them from sonorants and vowels in phonological rules and patterns.
| Class | Obstruction Type | Examples (English) | Examples (Japanese) |
|---|---|---|---|
| Stop | Complete blockage | /p, b, t, d, k, g/ | /p, b, t, d, k, g/ |
| Fricative | Narrow constriction | /f, v, s, z, ʃ, θ/ | /s, z, h, ɸ/ |
| Affricate | Stop + fricative | /tʃ, dʒ/ | /ts, tɕ, dʑ/ |
In Japanese phonology, the obstruent system has notable features:
- Voicing is predictive for rendaku: Rendaku (sequential voicing in compound words) applies to initial obstruents of the second element. If the second element already contains a voiced obstruent, rendaku is typically blocked (Lyman’s Law).
- Gemination (the small tsu っ) occurs with obstruents: /kk/, /ss/, /tt/, /pp/. You can’t geminate sonorants this way in standard Japanese.
- Limited voicing contrasts: Japanese has fewer voiced/voiceless pairs than English. /h/ has no true voiced counterpart (though it patterns with /b/ historically), and the fricative inventory is smaller.
Related Terms
See Also
Research
- Ladefoged, P., & Johnson, K. (2014). A Course in Phonetics (7th ed.). Cengage Learning. — Standard phonetics textbook with clear coverage of the obstruent–sonorant distinction.
- Vance, T. J. (2008). The Sounds of Japanese. Cambridge University Press. — Detailed treatment of Japanese obstruents, including gemination and rendaku patterns.