Speaker

Definition:
The point of view from which
the poem is being told

Example:
Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.      
In this poem, the speaker is "I"

Significance:
The speaker of a poem is important
because they can create a sort of
narrative and also changes the mood
by the way they tell the story.