Final answer:
In a speech, using personal stories allows a speaker to invoke concepts familiar to the audience, engage them emotionally, and make their message more relatable.
Step-by-step explanation:
In a speech, a speaker's use of personal stories allows them to invoke concepts that the audience is already familiar with.
Personal stories are relatable and can engage the audience emotionally, making them more receptive to the speaker's message. By sharing their own experiences, the speaker establishes a connection with the audience, creating a sense of trust and credibility.
Moreover, personal stories can serve as examples to illustrate the points the speaker is making, making abstract concepts more concrete and easier for the audience to understand.