This chart is for Korean vowels
In Korean a full sound is made by combining a consonant (자음) with a vowel (모음)
The chart in the question shows the pronunciation of the vowel sounds, but since the vowel characters are not used by themselves, their pronunciation is also the word used to refer to them
For example, the sound Ga is formed by the vowel ㄱ followed by the consonant ㅏ(ah) to give Ga (가)
Note that most Korean sounds do not have an exact English equivalent, so although ㅏ has been transliterated into English as 'ah', the 'h' at the end is not pronounced. The pronunciation is more like 'aa'
Also note that the consonants, on the other hand hand, each have their own name