Where does knowledge of grammar come from?

Grammar and Spelling: What the Research Says

Published in the Guardian (UK) 

The real reading problem in England is that policymakers in education have not read the research on literacy development (Report, 14 May). Results are very consistent: 1) Direct instruction in grammar and spelling produces very limited results. 2) Nearly all of our knowledge of grammar and spelling is acquired and absorbed through extensive reading. These studies have been appearing in scientific journals regularly for over the last 100 years. Policymakers are free to disagree with the research, but not free to ignore it.
Stephen Krashen
Professor emeritus, University of Southern California

Original article:  Eleven-year-olds wake up to compulsory spelling and grammar test (May 14)

 http://www.guardian.co.uk/education/2013/may/14/spelling-tests-english-sats-england

Some sources:

Cook, W. (1912) Should we teach spelling by rule? Journal of Educational Psychology 3, 316-325.

Cornman, O. (1902) Spelling in the Elementary School. Boston: Ginn.

Elley, W., I. Barham, H. Lamb, and M. Wyllie. (1976) The role of grammar in a secondary school curriculum. Research in the Teaching of English 10, 5-21.

Hammill, D., S. Larson, and G. McNutt. (1977). The effect of spelling instruction: A preliminary study. Elementary School Journal 78, 67-72.

For more sources, please see:

Krashen, S. (2004) The Power of Reading. Portsmouth, NH: Heinemann, and Westport: Libraries Unlimited.