Final answer:
Roosevelt developed the concept of freedom by presenting the Four Freedoms, aiming to reshape global human rights amidst the threats of Fascism during World War II. His impactful rhetoric fostered optimism and unity, influencing the creation of the United Nations.
Step-by-step explanation:
President Franklin D. Roosevelt developed the concept of freedom in his speeches by outlining the Four Freedoms which he believed were fundamental to human security and peace. Roosevelt described these as freedom of speech, freedom of worship, freedom from want, and freedom from fear. He articulated this vision during a time when the world faced the existential threat of Fascism, as evidenced by the events unfolding in Europe, which reshaped the understanding of freedom in the context of global human rights. In his inaugural address and subsequent fireside chats, Roosevelt used powerful rhetoric to convey optimism and engender a spirit of community. His language crafted a view of freedom that extended beyond national borders, aspiring to an international standard of human rights that would eventually influence the creation of the United Nations.