Motivated by the fact that English spelling c has two different pronunciations [k] and [s], this study investigates the relationship between English orthography c and its pronunciations as reflected in the c-spelled word production by Korean secondary school students. A total of 15 secondary school students produced the stimulus words designed for this study. The study revealed that the students had difficulties in associating the spelling c with the target-appropriate pronunciations because the overall inaccuracy rate amounted to 14.9% in the pretest. Further, the error rates in the pretest were different depending on the word groups; 33.3% for the c+i words, 20.2% for the c+e words, and 14.4% for the final c words. The most predominant error type was the replacement of the target sound [s] with [k], which occurred in the word groups of c+e and c+i. After two sessions of pronunciation training on the c-spelled words, the students showed a significant improvement in producing target words, and thus the overall inaccuracy rates were reduced to 5.5%. Likewise, the error rates for the word groups of c+i, c+e, and final c were significantly decreased to 12.7%, 7.6%, and 6.2%, respectively in the posttest 2. The results were further analyzed in terms of individual lexical items and individual participants and showed different learning processes depending on the lexical items and participants. Based on the findings of the study, implications for pronunciation teaching were drawn.