Definition:
A central vowel is a vowel sound produced with the tongue positioned in the center of the oral cavity along the front-back dimension — neither advanced toward the teeth (front vowel) nor retracted toward the throat (back vowel). On the IPA vowel chart, central vowels occupy the middle column.
In-Depth Explanation
The IPA vowel chart organizes vowels along two axes: tongue height (close/high to open/low) and tongue backness (front to back). Central vowels fall in the middle of the backness axis:
| Height | Front | Central | Back |
|---|---|---|---|
| Close (high) | /i/ | /ɨ, ɯ̈/ | /ɯ, u/ |
| Mid | /e/ | /ə/ (schwa) | /o/ |
| Open (low) | /æ/ (near-front) | /a, ɐ/ | /ɑ, ɒ/ |
The most common central vowels across languages:
- Schwa /ə/: The quintessential mid-central vowel, dominant in English unstressed syllables. Tongue in neutral position, no lip rounding.
- /a/: The open central vowel, often the most common vowel in languages worldwide. The Japanese /a/ (あ) is an open central or near-front vowel.
- /ɐ/: Near-open central vowel, found in German and Portuguese.
Central vowels in Japanese:
Japanese has five vowels: /a, i, ɯ, e, o/. Of these:
- /a/ is central (or near-central) in backness and open in height — it’s the “purest” open central vowel in the inventory
- /ɯ/ (the Japanese “u”) is technically back and unrounded, but in practice it’s centralized compared to the back rounded /u/ in many other languages. Phoneticians sometimes transcribe it as [ɯ̈] to indicate this centralization.
The Japanese /ɯ/ is one of the more challenging sounds for English speakers because English /u/ is back and rounded (“oo” in “food”), while Japanese /ɯ/ is centralized and unrounded. Producing English “oo” where Japanese expects /ɯ/ sounds noticeably non-native.
Related Terms
See Also
Research
- Ladefoged, P., & Johnson, K. (2014). A Course in Phonetics (7th ed.). Cengage Learning. — Standard explanation of the vowel chart and the central vowel column.
- Okada, H. (1991). Japanese. Journal of the International Phonetic Association, 21(2), 94–97. — Authoritative IPA illustration of Japanese vowels with discussion of /a/ and /ɯ/ centralization.