How does the language of Martin Luther King's "I Have a Dream" speech create an impact on the audience?

In his well-known "I Have a Dream" speech, Martin Luther King, Jr., employs
language that is compelling and filled with both figurative language andto urge his readers to
believe in a world of better possibilities for everyone.

Effective repetition
is one strategy that King uses to strengthen his argument. In the very beginning, he repeats
"one hundred years later" three times in a single (written) paragraph to underscore
the empty promises to the African American population. Later, he repeats his famous "I have
a dream" title line numerous times to highlight the ways that America could better fulfill
its promises to all people and to demonstrate the unity that is possible. This section is also
an excellent example of logos, the rhetorical strategy which appeals to the
audience's sense of logic.

King also uses metaphors, such as this
one:

Now is the time to rise from the dark and desolate
valley of segregation to the sunlit path of racial justice.

Thisdemonstrates the...