Two interactional strategies explicitly taught to learners of English in Hong Kong are how to check that the hearer understands what you are saying as you communicate and, conversely, how to check that you have understood another speaker's message. The forms of these strategies that are taught in Hong Kong schools are fairly limited. This study seeks, through examining authentic spoken discourse in the Hong Kong Corpus of Spoken English (HKCSE), to determine the ways in which these strategies are linguistically realised in real life communication, compared to the intuitions of materials writers that find their way into school textbooks. The findings suggest that more awareness of the realities of language use would be of benefit to textbook writers and teachers, enabling them to incorporate a wider and more accurate range of forms into their teaching materials, in order, in turn, to foster a more accurate awareness of language and language use in their learners. The approaches of corpus-driven research and data-driven learning are useful; through these, language learners can also become language researchers themselves, engaging themselves in the examination and analysis of corpus data.