Aptitude refers to an individual’s natural ability or potential to learn and perform a particular type of activity effectively. In the context of a language learner, aptitude is the learner’s potential to acquire and use a language successfully. It is different from present language achievement because aptitude indicates the capacity to learn in the future, whereas achievement reflects what the learner has already learned. Measurement of language aptitude is therefore useful for understanding individual differences among learners and for planning suitable language teaching. Language aptitude generally includes several abilities that contribute to successful language learning. One important ability is phonetic coding, which refers to the capacity to identify, distinguish, and remember unfamiliar sounds. A learner with good phonetic coding ability can more easily recognize differences between sounds and develop accurate pronunciation. Another component is grammatical sensitivity, which is the ability to recognize the grammatical functions of words and understand how they operate within sentences. This ability helps learners understand sentence structure and grammatical patterns. A