Korean college students’ self-directed learning to learn English language is essential but there is little literature regarding the relationship between their SDEL and English speaking ability development. In this paper, we examined the score development of their SDEL and English speaking ability in 6 months by means of pre- and post-tests. The English speaking test assessed task completion, fluency, pronunciation, grammar, language use accuracy, coherence with 9 scales. SDEL survey consisted of interpersonal relationship, self-esteem, self-confidence, ability to overcome English anxiety, goal-orientedness, motivation, self-directedness, information process ability, self-understanding, SDEL level. The results showed that although the participants’ English speaking test and SDEL scores slightly increased or decreased, mean differences of both measures were not statistically significant between pre- and post-tests. In addition, there was a low correlation between their SDEL ability and English speaking scores but self-confidence showed a mild correlation with the holistic and fluency scores. Hence, the findings pointed out that Korean college students’ SDEL ability and their English speaking ability were not abruptly developed in such a short period. Although there was a low correlation between them, we may expect their speaking ability improvement along with the increase in their self-confidence. Finally, we discussed some characteristics of the relationship between English speaking and SDEL abilities of an individual participant.