If you read the full article, you’d see they specifically mention that they were studying ‘huh’ in the context of “other-initiated repair” (see the article for

If you read the full article, you’d see they specifically mention that they were studying ‘huh’ in the context of “other-initiated repair” (see the article for a definition), and they noted that ‘huh’-like words often have additional contextual uses, such as signifying a question, but those were beyond the scope of this research.