A Muslim invited to speak at an interfaith event on controversial issues should prepare by:

1. **Researching the Topic**: Understand the controversial issues thoroughly from both Islamic and broader perspectives.

2. **Clarifying Objectives**: Determine the goals of the speech, focusing on promoting understanding, respect, and constructive dialogue.

3. **Gathering Knowledge**: Use reliable sources to support their points, drawing from the Qur’an, Hadith, and scholarly interpretations.

4. **Practicing Respectful Communication**: Prepare to address differing views with empathy and respect, emphasizing common values and fostering mutual respect.

5. **Engaging in Dialogue**: Be ready to listen actively and engage in discussions, encouraging open and respectful exchanges.

By preparing thoughtfully, they can effectively contribute to meaningful interfaith dialogue.