Học vần eng, ec, ong, oc, ông ôc: https://www.youtube.com/watch?v=nDjQlUAbaFo&t=1637s
Vần um, up, uôm, uôp: https://www.youtube.com/watch?v=H9lGRbpDwEc&t=78s
Vần iêm, iêp, ươm, ươp: https://www.youtube.com/watch?v=DnxGggm6p6U&t=200s
Vần ôm, ôp, ươm, ơp: https://www.youtube.com/watch?v=WM8F4msvijw&t=134s
Vần im, ip, om, op: https://www.youtube.com/watch?v=tU0M7Sg2hx0&t=685s
