learning by sight word first of by sounding it out first- many can move between the two with little problem

so from what i've read and from my own experience, it seems that teaching by the sight word method can hinder the ability to blend by sound, at least in some children.  however, i don't think this is universally true. for one, it is standard practice in the district where i teach to teach letter sounds along with sight words in kindergarten.  the majority of the kids do alright with this mix of methods.  also, when i was teaching english in taiwan, which is mandarin speaking, i taught my students to sound out words using phonics, and the vast majority could do it even though they had been learning chinese characters by sight/rote for years.  now chinese children first learn the blend sounds using a pronunciation system called pinyin in china and zhuyin in taiwan,  so their first exposure is to sounding out words.  they then switch to sight 'character' memorization, and many are taught all their english vocab using the sight word method.  even with those habits, they can switch to learning to blend with phonics.  so it seems to me that many students can switch between the two methods.  but i still believe there is a vulnerable population that can not switch. more on this later.