Abstract: The research explored the effect of morphemic analysis
awareness on ESL secondary school students’ vocabulary acquisition.
The quasi-experimental study was conducted with 100 ESL
secondary school students in two experimental groups (inflectional
and derivational) and one control group. The students’ vocabulary
acquisition was assessed through two measures: Morph-Analysis Test
and Morph-Vocabulary Test in the pretest and posttest before and
after an intervention programme. Results of ANCOVA revealed that
both the experimental groups achieved a significant score in Morph-
Analysis Test and Vocabulary-Morphemic Test. However, the
inflectional group obtained a fairly higher score than the derivational
group. Thus, the findings of the research are discussed in two main
areas. First, individual instructions of two types of morphemic
awareness have contributed significant results on inflectional and
derivational awareness among the ESL secondary school students.
Nevertheless, derivational morphology achieved a significant but
relatively smaller amount of effect on secondary school students’
morphological awareness compared to inflectional morphology in
this research. Second finding showed that the awareness of
inflectional and derivational morphology was found significantly
related to vocabulary achievement of ESL secondary school students.
Nevertheless, inflectional morphemic awareness had higher
significant effect on ESL secondary school students’ vocabulary
acquisition. Despite these findings, the study implies that morphemic
analysis awareness can serve as an alternative strategy for ESL
secondary school students in acquiring English vocabulary.