Four characteristics of language proficiency which are formal mastery, semantic mastery, communicative capacity, and creativity are best assumed to develop simultaneously from the start. They complement each other through the learning process. During the first stage of learning, the learner is preoccupied with language as a system of communication which is arduous and strictly limited. The learner is dependent on help both in learning and in using it for communication. This dependence phase ends as soon as the learner feels confident enough to use the language, however defectively, for his own purpose. The present study is an attempt to understand if code-switching conducted as a communicative strategy leads to earlier entrance of the students into communication phase and consequently to the establishment of early oral proficiency. The study was conducted on post-beginner female EFL subjects at a language school in Karaj, Iran. In order to have homogeneous subjects and to validate subsequent speaking test to be administered in the course of the study, a teacher-made achievement test was given to the subjects. After random assignment of the subjects to the control and experimental groups, the subjects were asked to deliver a five-minute description on a picture. The pretest was given to both groups to test their speaking ability at the beginning of the study and make sure that they belonged to the same population. In the posttest, which was run after giving the treatment to the experimental group, students took another speaking test with the same characteristics as the pretest. Comparing the means of the posttests indicated that the subjects in the experimental group had a significantly better performance in their speaking compared to the control group. It was concluded that the use of code-switching does improve the speaking skill of EFL learners and can be used as a technique to enhance this skill.