Final answer:
The speaker in the provided excerpts from Shakespeare's Macbeth is primarily Macbeth, who is the main character and interacts with other characters in his quest for power.
Step-by-step explanation:
In the Shakespearean play Macbeth, the speaker in the excerpts provided is primarily Macbeth himself. Macbeth is the main character and protagonist of the play who interacts with several other characters like the witches, Banquo, and Macduff. Macbeth's dialogue reveals the prophecies given to him by the witches and his subsequent reactions, such as his confusion about being named thane of Cawdor and his contemplation of the possibility of becoming king, as indicated by the lines 'But how of Cawdor? the thane of Cawdor lives,' and 'All hail, Macbeth! hail to thee, thane of Glamis!'