The instructor sings the vowels to the tune of a hymn (can't put my finger on which one...I can vaguely recall some of the words in Korean...I'll have to ask my mom), demonstrating the direction of the written form of the vowel with her arms.
In the video, the instructor wants to sing the song "duh bbal-lee" - more faster. A student asks whether it's "P or B" (pal-ee or bal-ee)? The teacher deflects this question and says she'll explain later (bc it's actually a BB). Anyway, this is an example of the distinctions of sound that seem troublesome to the husband. d or t? g or k? p or b? j or ch? Of course, to me the distinction is recognizable, but to the non-native Korean speaker, yes honey, "It's complicated." We'll work on it. =)
[At this point, I am realizing that it would be helpful if I learned how to load the Korean-language onto my laptop so that I could actually type out these characters, but I haven't reached that level of tech-savy yet. But I bet it's really easy to do on the Ipad 2! hint! hint! wink!]