ENGLISH:
Pronunciation was an essential component of speaking skills; however, many tenth grade students at SMA N 1 Simpang Teritip experience difficulties in pronouncing certain English consonant sounds such as /θ/, /ʃ/, /t/, /d/, and /s/ due to mother tongue interference and limited pronunciation practice. This study aimed to find out the effectiveness of the tongue twister technique in improving students’ English pronunciation ability. The research employed a quantitative approach using a quasi-experimental design with a non-equivalent control group involving 63 tenth grade students divided into an experimental group (32 students) and a control group (31 students). Data were collected through pronunciation oral tests administered as pre-test and post-test, and students’ performances were assessed by two raters to ensure reliability. The data were analyzed using normality test, homogeneity test, paired sample t-test, and independent sample t-test at a significance level of 0.05. The results showed that the experimental group’s mean score increased significantly from 33.91 (SD = 8.59) in the pre-test to 63.59 (SD = 10.10) in the post-test (t = -14.433, df = 31, p = 0.000), while the control group improved from 34.03 (SD = 8.21) to 48.23 (SD = 9.79) (t = -14.390, df = 30, p = 0.000). Furthermore, the independent sample t-test of the post-test scores revealed a significant difference between the experimental and control groups (t = 5.739, df = 62, p = 0.000). These findings indicate that the tongue twister technique was statistically effective in improving students’ pronunciation ability.