Ah, if you are going to look at phonemic awareness and the studies conducted in this area....you must read the seminal paper by Gary Troia on how poor treatment studies were/are in this area. I personally think that the focus on splinter skills like phonemic awareness and teaching them in a de-contextualized manner is quite problematic. See Troia paper and a presentation I did below in this area.
'The ability to pronounce phonemes ( the smallest units of sound) depends partly on the way in which a very young child can coordinate tongue, palate, larynx, lips and other arts of the vocal motor apparatus. This ability also depends on the child's ability to hear each phoneme. If a child has a hearing deficit then the child may not hear the beginnings or ends of words and miss those phonemes. Also phonemic ability depends on one's culture. If there is no "th" sound then French children , for example, will have difficulty pronouncing words in English that begin with th and may instead say "wiz" instead of "with". . Children in Japan will hear l and r the same. So cultural differences in omitting certain phonemes or having phonemes not in another language will cause some children troubles to hear and to pronounce those phonemes. Also , some languages use phonemic clusters that do not exist in other languages. " Ngoro Ngoro " crater is fine for an African child to pronounce, but the phoneme combination may be difficult for an English speaking child to learn to say. Phonemic consonant clusters are particularly difficult for some persons. Thus, saying "nuclear" clearly has been difficult even for some adults , who instead say " 'nucular.' Attentiveness to the source of a child's troubles with phonemes can assist a loving adult to provide more focused help for that child! .