“Although it is not necessary to understand that a word is irregular to be able to pronounce it, the same is not true when it comes to clear, direct, teaching of reading and writing skills. In order to implement synthetic phonics programs, teachers must be able to recognize words that can be successfully decoded (e.g., “dog”) from those that cannot (e.g.,“one”). But unfortunately, classroom observations have revealed that teachers frequently give children frustrating instructions by asking them to “sound out” words that are, at least partially, irregular (Spear-Swerling & Brucker 2004).”
Ref: Megan Ladd & Sandra Martin-Chang & Kyle Levesque (2011) ‘Parents’ reading-related knowledge and children’s reading acquisition’ Ann. of Dyslexia (np – online first copy)
Reference is to: Spear-Swerling, L., & Brucker, P. O. (2004). Preparing novice teachers to develop basic reading and spelling skills in children. Annals of Dyslexia, 54(2), 332–359.