Hekiganroku - Case 70: Isan's "Speak, Master"

Isan, Goho and Ungan were all attending upon Hyakujo. Hyakujo asked Isan,
  "How does one speak with one's lips and throat closed?"
Isan said,
  "I'd rather have you speak, Master."
Hyakujo said,
  "I might as well speak to you, but then, I would lose my Dharma descendants."