The purposes of this classroom research were: 1) to develop the English vocabulary speaking skills of Grade 4 students using Active Learning activities at Pakse Teacher Training College Demonstration Primary School, and 2) to compare the students' learning achievement before and after implementing the Active Learning approach. The experimental group consisted of 25 Grade 4 students selected from the Demonstration Primary School. The research instruments comprised two types: 1) pre-test and post-test achievement tests for English speaking skills, and 2) a 5-point Likert scale teacher performance observation form covering 5 dimensions of Active Learning instruction. Data were analyzed using percentage, mean (X), and standard deviation (S.D.). The research findings revealed that: 1) the students' learning development in English speaking skills through Active Learning activities showed significantly higher post-test scores $(\overline{X}=8.08$, $S.D.=1.11)$ compared to their pre-test scores $(\overline{X}=5.72$, $S.D.=0.79)$, with a statistically significant difference at $p<0.05$ $(t(25)=10.59)$. 2) The evaluation of the Active Learning instructional management across all 5 dimensions was overall at a high level $(\overline{X}=3.50$, $S.D.=0.55)$. Analytically, the teacher dimension obtained the highest mean score $(\overline{X}=3.68$, $S.D.=0.70)$, followed by lesson content $(\overline{X}=3.66$, $S.D.=0.68)$, measurement and evaluation $(\overline{X}=3.61$, $S.D.=0.65)$, students $(\overline{X}=3.45$, $S.D.=0.62)$, and instructional activities $(\overline{X}=3.27$, $S.D.=0.69)$ respectively.