Phonics works, when it does, by transference from an existing large speakinglistening vocabulary. If there is no such vocabulary or if the transfer mechanisms of hearing and speaking are faulty then phonics will fail.
This has been well demonstrated by many children with Down's syndrome who have learnt to read by first acquiring a sight vocabulary. This then has a beneficial effect on their speech - often non-existent previously.
One of the arguments used by phonics specialists is that there is a limit to the number of words that can be recognised in a sight vocabulary.
There are two counter arguments. The first is that all expert readers are sight readers with immediate sight recognition vocabularies of many thousands of words. The second is that expert listeners have an immediate recognition vocabulary of many thousands of words, relying on sound alone and it must be easier to build up a large recognition vocabulary based on vision and sound combined, rather than on sound alone.
Leslie Duffen Green Lane Ilsington Newton Abbot, Devon