Basic & Simple & Compound vowels
Using the basic vowels Cheon-ji-in ( ·, ㅡ, ㅣ), single-dot vowels ( ㅗ, ㅏ, ㅜ, ㅓ ) were created.
Subsequently, by adding one more dot, double-dot vowels ( ㅛ, ㅑ, ㅠ, ㅕ ) were formed.
‘ · ‘ Dot (Cheon = heaven) is a sound that was used in the Joseon Dynasty, but has since disappeared.
