This informality is used as a bonding technique and is easily emphasized by tone of voice or stress during the speech. Lastly, Kennedy relies heavily on appeal to American values as well as on positive talk (we are good theme) about the United States, soliciting justification, support and sympathy from the audience, at times bordering on propaganda.
And then shall Cuba be welcomed back to the society of free nations and to the associations of this hemisphere.
Kennedy begins with a biblical shall, as if the US was the one to bless Cuba with freedom, then moves onto insinuating that Cuba is currently being excluded from not just the free nations (since it is currently unfree) but also from the associations of this hemisphere, hinting there is a club-like society of free and unfree nations to which Cuba wants to belong.
Finally, Kennedy closes with a Biblical reference to a chosen path, and to the one, potentially alluding to Jesus, lifting the American character, courage and lastly the commitment to the world, directly referencing Winthrop.
Overall, Kennedy delivers a solid, well thought-out speech, successfully employing audience involvement strategies and the appeal to American values, which are well emphasized by a television broadcast.