 Text corpus

A text corpus is a collection of language samples assembled according to stated criteria for systematic analysis. It can contain written material or transcribed speech; selection, recording conventions and linguistic annotation determine what questions it can answer. A collection's size alone does not make it representative of every speaker or situation.^[ref]

Suppose a toy text corpus contains 20,000 word tokens and 60 occurrences of a chosen form. Its observed rate is $60/20000=0.003$, or 3,000 per million tokens. A second collection needs a comparable denominator before counts are compared. Keeping interview and news samples separately identifiable helps distinguish a difference in language use from a difference in the mixture of text types. A text corpus thus turns examples into countable evidence while preserving the need to justify sampling.