The purposes of this research were; (1) to study problems on English vocabularies pronunciation of Prathomsuksa 3 students, (2) to develop computer-assisted instruction lessons for enhancing skills on English vocabularies pronunciation, (3) to practice skills on English vocabularies pronunciation of Prathomsuksa 3 students and (4) to evaluate English vocabularies pronunciation of Prathomsuksa 3 students after using of computer-assisted instruction lessons. Research area was Anuban Nakhon Ratchasima School under Nakhon Ratchasima Primary Educational Service Area Office 1, Minis try of Education and research duration was in the first and second semester of 2016 academic year.
The study revealed that:
1. The problems on English vocabularies pronunciation of Prathomsuksa 3 students were in high level. Their causes came from; students take caring, times of learning, personnel in the school, communication and technology and fundamental differences of students; respectively.
2. The development of computer-assisted instruction lessons for enhancing skills on English vocabularies pronunciation of Prathomsuksa 3 students was consisted of (1) 9 lessons of computer-assisted instruction, (2) 18 sets of learning management plans, (3) achievement test and (4) satisfaction questionnaire. The computer-assisted instruction lessons had its efficiency of 80.26/89.26 that higher than specified criteria.
3. The practice skills on English vocabularies pronunciation by instructional experiment in accordance with learning management plans found that the effectiveness of lessons at the post- was higher than the pre- learning. In aspect of attitude, it was found that students had their satisfaction on learning management in the highest level.
4. The evaluation of English vocabularies pronunciation of Prathomsuksa 3 students found that students developed their skills on English vocabularies pronunciation increasingly.
The students with different basic of language could develop their skills on English vocabularies pronunciation and lessons could solve their problems on English vocabularies pronunciation as well.