Final answer:
The persuasive technique in Martin Luther King Jr.'s speech is pathos, an emotional appeal, aimed at highlighting the injustices faced by African Americans and the need for reform.
Step-by-step explanation:
The persuasive technique being used in Martin Luther King Jr.'s I Have a Dream speech is pathos. King utilizes emotionally charged language to appeal to his audience's emotions and to evoke a sense of urgency and outrage over the injustices faced by African Americans. By describing the struggles of African Americans with vivid metaphors such as living on a 'lonely island of poverty' and being in the 'chains of discrimination,' King seeks to persuade his listeners of the critical need for civil rights reform.