What is "to open one's mouth"

Open \O"pen\ v. t. [imp. & p. p. Opened; p. pr. & vb. n. Opening.] [AS. openian. See Open,a.]

1. To make or set open; to render free of access; to unclose; to unbar; to unlock; to remove any fastening or covering from; as, to open a door; to open a box; to open a room; to open a letter.

   And all the windows of my heart I open to the day.
   --Whittier.

2. To spread; to expand; as, to open the hand.

3. To disclose; to reveal; to interpret; to explain.

   The king opened himself to some of his council, that he was sorry for the earl's death.
   --Bacon.

   Unto thee have I opened my cause.
   --Jer. xx. 12.

   While he opened to us the Scriptures.
   --Luke xxiv. 32.

4. To make known; to discover; also, to render available or accessible for settlements, trade, etc.

   The English did adventure far for to open the North parts of America.
   --Abp. Abbot.

5. To enter upon; to begin; as, to open a discussion; to open fire upon an enemy; to open trade, or correspondence; to open an investigation; to open a case in court, or a meeting.

6. To loosen or make less compact; as, to open matted cotton by separating the fibers.

   To open one's mouth, to speak.

   To open up, to lay open; to discover; to disclose.

   Poetry that had opened up so many delightful views into the character and condition of our ``bold peasantry, their country's pride.''
   --Prof. Wilson.