Corpus planning is one aspect of language planning, in the well-known classification of Kloss (1969): It refers to modifications in vocabulary, grammar, or writing, and it contrasts with status planning.
The term corpus planning is misleading in that the planning does not affect any kind of corpus, but the structure of a language (which after a successful change will of course lead to changes in corpora).
- Kloss, Heinz. 1969. Research possibilities on group bilingualism: a report. Quebec: International Center for research on Bilingualism.