Spelling of stop consonants after /s/ by children and adults

Two experiments examined the way in which kindergarteners, first graders, and adults spell syllables like /spa/, /sta/, and /ska/. The second consonants of these syllables are standardly spelled as the voiceless stops P, T, and C/K. From a phonetic standpoint, however, the consonants could be spelled as the voiced stops B, D, and G. The proportion of voiced spellings was found to decrease with reading level: The nonstandard spellings were fairly prevalent among children, but almost nonexistent among adults. Nonetheless, most adults could choose the phonetically plausible voiced spellings over phonetically incorrect spellings.