Bob Holmes, a science journalist, uncovers the surprising significance of interjections like 'um' and 'huh' in conversation, revealing how they regulate dialogue and foster understanding. Meanwhile, Ronan McCarthy, a biomedical sciences professor, shares groundbreaking research on saccharin, showing its potential to combat antibiotic-resistant bacteria by disrupting their membranes. Together, they discuss how these seemingly trivial elements can have profound implications for communication and health.