What about phonics?

How useful is it to incorporate phonics, so central these days to the teaching of English as a first language, into the teaching of English to speakers of other languages?
For children with English as a first language, the main function of phonics is to help them learn how to read: in other words, to grasp that letters represent sounds, and to master the process of decoding.
But learners of English as a second language already know how to read. They already understand the process of decoding. What they need to learn is the code that applies in this new language to the relation between sounds and spelling. And here, of course, English is disappointingly unhelpful. There are different ways of spelling the same sound (vowels are the main offenders) and so many words whose spelling seems to have no logic at all. Take a vowel digraph like ea, which makes a different sound in team to the one it makes in head, whilst in the word read, the sound it makes depends on whether it refers to the past or present! Compared to a language whose phonetic system is very logical, like German or Spanish, it can seem inappropriate to apply the word ‘system’ to English spelling at all.
But such rules as there are provide a guide at least, and it is arguably an advantage that most of the hardest, most illogical spellings belong to the commonest words (what, one, two, was…), so students will get to know them because they’ll meet them a lot.
In general, material designed for English speaking children who are learning to read is not appropriate for learners of English as a second language. This is not only because the former may be aimed at much younger children. Such material is also based on the premise that English speaking children will have a wide vocabulary before they even start learning to read. The words they are taught to read first are chosen because they illustrate basic sounds: e.g. pat pet pit pot. It is assumed that they will know their meaning. To an ESOL student, most of these would be meaningless.
One of the most effective ways of using phonics is to draw students’ attention to groups of words they already know that include the same sound. For example: I, hi, nice, my, why, right, eye. While this will underline the fact that there are different ways of spelling the sound, it allows you to highlight the common patterns as well as to point out the crazy (but important) exceptions!