 This means, for example, that while one can compare speech by men and by women, one cannot compare speech "to" women and "to" men.The nature of the BNC as a large mixed corpus renders it unsuitable for the study of highly specific text-types or genres, as any one of them is likely to be inadequately represented and may not be recognisable from the encoding.For example, there are very few business letters and service encounters in the BNC, and those wishing to explore their specific conventions would do better to compile a small corpus including only texts of those types.