Vowels in Korean are classified as Yang (positive, light, not heavy), Eum (negative, dark, heavy), and neutral.
The Yang vowels are ㅏ
and ㅗ
.
The Eum vowels are ㅓ
and ㅜ
.
The neutral vowels are ㅣ
and ㅡ
When combining vowels to make diphthongs:
Yang vowels can only combine with other yang or neutral vowels.
(example: ㅘ,
ㅚ)
Eum vowels can only combine with other eum or neutral vowels.
(examples: ㅝ,
ㅟ)
Neutral vowels can only combine with other neutral vowels.
(example: ㅢ)