Hangul is an alphabet. That is, each letter corresponds to what linguists refer to as a phoneme ... So in Korean, to write the sound /ka/, like in English, you write the two letters “k” ㄱ + “a” ㅏ to ...

Then they’ll get stumped mumbling while they think desperately for ‘k’ words ... We use letters selected from a standard phonetic, or spelling, alphabet so nobody fumbles for words.