Linguists once dismissed interjections such as um, huh and mm-hmm as meaningless noise, but recordings of everyday speech show they are extremely common, appearing roughly once in every seven utterances. Researchers led by Mark Dingemanse at Radboud University found that all 31 languages surveyed had a short, neutral repair signal similar to huh, used to flag a misunderstanding. Mm-hmm works as a continuer that tells a speaker to keep going, and its closed-mouth form signals that the listener does not want the floor. In a classic experiment, students who failed to give listening signals told less well-crafted stories. Other interjections help set what each person knows, such as Canadian eh, which flags a statement as news to the speaker. Linguists now see these small words as central to how conversation works.

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.