Open website Speaking.detim.vn. Notification "Speaking.Detim.vn wants to use your microphone" -> click "Allow" (Figure - I-1)
If you don't see notification figure then you click "Secure" (near https://speaking.detim.vn) -> click "Allow" (Microphone) (Figure I-2)
Open browser mobile (Google Chrome) and go Speaking.detim.vn. Notification "Speaking.Detim.vn wants to use your microphone" -> click "Allow" (Figure - II-1)
If you don't see notification figure then you touch "sign clock" (near https://speaking.detim.vn) (Figure II-2)
Touch "Site Settings" (Figure II-3)
Touch "Access your microphone" -> choose "Allow" (Figure II-4)