Rhetorical devices are language tools used to make speakers’ arguments both appealing and memorable. In “I Have a Dream”, Martin Luther King Jr. extensively uses repetitions, metaphors, and allusions. Other rhetorical devices that you should note are antithesis, direct address, and enumeration.
MLK’s speech includes several historical, religious, and cultural allusions. An allusion is a reference to an event, a person, media, or literature that the speaker finds relevant for the topic and purpose of his speech.
For example, King alludes to Abraham Lincoln and the Emancipation Proclamation which officially ended slavery: “Five score years ago, a great American, in whose symbolic shadow we stand today, signed the Emancipation Proclamation.” (ll. 5-7). Note that this allusion is further emphasized by the setting of Martin Luther King’s speech, which is made outside the Capitol (the seat of American government). The building contains a large statue of Abraham Lincoln, which can be seen in the video.
Furthermore, the speaker also alludes to the rights guaranteed by the US Constitution and Declaration of Independence: “the ‘unalienable Rights’ of ‘Life, Liberty and the pursuit of Happiness.’ ” (ll. 26-27); “ ‘We hold these truths to be self-evident, that all men are created equal.’ ” (ll. 115-116).
These allusions are meant to remind the audience that, officially, African Americans should have the same rights as white Americans. The same idea is strengthened by explicitly mentioning the US Constitution and the Declaration of Independence, which both claim that Americans have the right to freedom: “When the architects of our republic wrote the magnificent words of the Constitution and the Declaration of Independence…” (ll. 21-23).
Such historical references are meant to create ethos, giving the speaker and his arguments authority and credibility.
Later, MLK alludes to the American Dream – “I still have a dream. It is a dream deeply rooted in the American dream.” (ll. 112-113)— a reference that is also meant to remind the audience that according to American principles everyone should have equal opportunities to follow their dreams, including African Americans.
The speech also includes the lyrics of an American patriotic song, which helps the speaker to connect the situation of African Americans seeking freedom with the freedom sought by the Founding Fathers of America:
My country 'tis of thee, sweet land of liberty, of thee I sing.
Land where my fathers died, land of the Pilgrim's pride,
From every mountainside, let freedom ring! (ll. 151-153)
Finally, the speaker makes several biblical references which are in line with his vocation as a church minister, and which help him use religiou...