Mid Vowel

Definition:

A mid vowel is a vowel produced with the tongue at an intermediate height in the oral cavity — between close (high) vowels and open (low) vowels. The IPA further divides mid vowels into close-mid (/e, o/) and open-mid (/ɛ, ɔ/), with true mid (/e̞, o̞/) falling between them.

In-Depth Explanation

Mid vowels occupy the center of the vowel height scale:

Many languages don’t distinguish close-mid from open-mid and simply have one “mid” vowel at each frontness position. Japanese is one of these languages.

Mid vowels in Japanese:

Japanese has two mid vowels:

• /e/ (え) — A mid front unrounded vowel. Phonetically it falls between close-mid /e/ and open-mid /ɛ/, typically transcribed as [e̞]. It does not diphthongize like English “say” (/eɪ/).
• /o/ (お) — A mid back rounded vowel. Phonetically between close-mid /o/ and open-mid /ɔ/, typically transcribed as [o̞]. It does not diphthongize like English “go” (/goʊ/).

The key learning point for English speakers: English mid vowels are typically diphthongs — they glide from one position to another (/eɪ/ for “say,” /oʊ/ for “go”). Japanese mid vowels are pure monophthongs — the tongue holds steady in one position. Producing the English glide when speaking Japanese is one of the most common pronunciation errors and immediately marks a speaker as non-native.

Practice tip: Say English “bed” (/ɛ/) and hold that vowel steady — that’s close to Japanese /e/. Say “caught” (/ɔ/) and hold — that’s close to Japanese /o/. The key is removing any movement.

Related Terms

• Close Vowel
• Open Vowel
• Front Vowel
• Back Vowel
• Schwa

See Also

• Japanese Phonology
• Sakubo

Research

• Ladefoged, P., & Johnson, K. (2014). A Course in Phonetics (7th ed.). Cengage Learning. — Vowel height distinctions and acoustic correlates of mid vowels.
• Okada, H. (1991). Japanese. Journal of the International Phonetic Association, 21(2), 94–97. — Precise IPA transcription of Japanese mid vowels as true-mid [e̞, o̞].