Mrz is making a really good point.
IM(limited)E pupils that struggle with reading are saying l-i-g-h-t and then are utterly baffled as to why the word has no g sound in it.
ATM I am picking sounds and emphasising that it is a sound made up of letters. This can be quite a novel concept apparently - and the pupils I am teaching are years 3 - 5.
I think it is difficult to get them to look for patterns/sounds that they know instead of just the letter on its own.
So, when I look at the word 'light' I see l - igh - t because I know that more often than not, the 'igh' makes an 'eye' sound.
The pupils I am teaching see luh i guh huh tuh - there is no way they are goign to make l eye t out of that!