Babel is a hubbub, or a confused mix of voices. It might be hard for your grandfather to hear in a restaurant with background music and a loud babel of conversation.
The babel of voices in a hotel's hall at night makes it difficult to sleep, and the babel of kids talking all at once is frustrating for a new teacher. Babel can also mean a figurative noise or conversation: "The babel of expert opinions on this issue is confusing me." Babel comes from the Biblical "Tower of Babel" story, in which God confused the builders of a tower to heaven by making them speak different languages.