Journal of English Language and Education ISSN 2597- 6850 (Onlin.
, 2502-4132 (Prin.
Journal Homepage: https://jele.
id/index.
php/jele/index Article Analysis of Thai Students' Ability in Composing Using Indonesian Affixes in Southern Thailand https://doi.
org/10.
31004/jele.
*A-esah Kehra.
Syamsuyurnitaab 12 Program Studi Pendidikan Bahasa Indonesia.
Fakultas Keguruan dan Ilmu Pendidikan.
Universitas Muhammadiyah Sumatera Utara.
Indonesia Corresponding Author: aesahkehra091003@gmail.
ABSTRACT
This study aimed to analyze the ability of 30 Matayom 5 students .
quivalent to Grade 11 high schoo.
at Thammasat Whittaya School.
Southern Thailand, to write essays using Indonesian affixes correctly and to identify the most common types of affixation errors.
Mastery of affixes .
refixes, suffixes, infixes , and confixe.
is considered crucial because even the smallest error can affect the overall quality of the essay, impacting both meaning formation and grammatical accuracy.
Using a descriptive qualitative approach, data were collected through writing tests, observations, and teacher interviews.
The analysis revealed that students' abilities were moderate, with a high tendency for errors in prefixes, suffixes, and confixes, particularly related to phonological changes and grammatical inaccuracies.
Infix errors were the least common.
These findings underscore the urgent need to strengthen morphology learning through explicit strategies, ongoing contextual practice, and the development of teaching materials specifically tailored to the needs of Thai students.
Keywords: Indonesian Affixes.
Affixation Errors.
Matayom 5 Students.
Essay Writing.
Morphology Learning Article History:
Received 17th December 2025
Accepted 08th January 2026
Published 10th January 2026
INTRODUCTION
In the field of Second Language Acquisition (SLA), morphology plays a crucial role in connecting lexical knowledge with grammatical competence.
Morphological knowledge enables learners to understand how words are formed, modified, and used accurately within sentences, making it a foundational element of second or foreign language writing.
As the national language of Indonesia.
Indonesian has a relatively complex morphological system, particularly in its use of affixation.
Learners are required to master various prefixes, suffixes, confixes, and infixes, which significantly alter word meaning and grammatical category (Hasana, 2.
This complexity presents a unique challenge for foreign Morphological awareness is especially important in writing because it allows learners to manipulate word forms to express precise meanings and appropriate grammatical Through affixation, learners can transform base words into different word classes, enriching their written expression and improving textual coherence.
Affixation is a morphological process in which affixes are attached to root words to generate new meanings distinct from the original lexical forms.
For this reason, mastery of Indonesian affixes is considered a core component of writing proficiency, as it directly affects accuracy, clarity, and stylistic appropriateness in written texts (Putra & Zain, 2.
Producing high-quality Indonesian writing requires learners to manage multiple linguistic levels simultaneously, including morphology, syntax, semantics, and pragmatics.
When learners lack sufficient morphological competence, errors in word formation occur, which can obscure meaning and reduce the overall comprehensibility of their writing (SaAodiyah, 2.
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Analysis of Thai Students' Ability in Composing Using Indonesian Affixes in Southern Thailand Affix acquisition difficulties among L2 learners often stem from factors such as mother tongue interference, limited grammatical knowledge, and insufficient vocabulary mastery.
Affixation poses particular challenges because it demands an understanding of how word forms change categories and meanings, rather than simply adding elements to a base word (Tepu Sitepu, 2.
Furthermore, affixes function within sentence structures and require learners to select forms that align with syntactic and semantic demands, a process that involves considerable cognitive effort (Khairunnisyah & Firmansyah, 2.
These challenges are intensified by limited access to learning infrastructure abroad, such as Indonesian language corpora and standardized proficiency assessments, which are vital for identifying and correcting nonstandard usage (Melinda & Febriyana, 2.
In Thailand, the growth of Indonesian for Foreign Speakers (BIPA) programs across various educational levels highlights the increasing importance of Indonesian as a tool for education and regional diplomacy (Syamsuyunita, 2024.
Saragih, 2.
However.
Thai learners frequently encounter morphological errors, particularly in affixation.
Analyzing these errors provides valuable insights into learnersAo cognitive and linguistic challenges and serves as a foundation for developing more explicit instructional strategies and context-based teaching materials (Lubis & Rahayu, 2.
METHOD
This study employed a descriptive qualitative approach to provide a nuanced and indepth analysis of the morphological abilities of Thai students.
While the data collection involved writing tests that produced frequency data, the study remains qualitative as it focuses on error analysis (EA) to describe the nature, causes, and patterns of linguistic deviations (Indrawan, 2.
The quantitative elements .
uch as error frequencie.
serve as a foundation for a deeper qualitative interpretation of the students' interlanguage development.
The researcher acted as the primary instrument in identifying, classifying, and interpreting the contextual meaning behind each affixation error.
Respondents The subjects were 30 Matayom 5 students .
quivalent to Grade 11 high schoo.
at Thammasat Whittaya School.
Southern Thailand.
They were selected because they are actively enrolled in the Indonesian for Foreign Speakers (BIPA) program.
Given the specific and focused nature of the population, this study utilized saturated sampling .
ensus samplin.
, where all 30 students in the class were included as participants to ensure a comprehensive overview of the group's morphological challenges.
Instruments The research utilized three primary instruments: a writing test, observation sheets, and interview guidelines.
The writing test was designed to elicit natural language production, specifically the use of prefixes, suffixes, infixes, and confixes in a continuous essay.
Observation sheets were used to document the classroom environment and linguistic behavior, while interview guidelines provided structural support for collecting qualitative insights from Indonesian language teachers regarding the students' learning difficulties.
Procedures The study was conducted over 28 days at Thammasat Whittaya School.
It began with a preliminary observation of the Matayom 5 classroom to assess the learning environment.
This was followed by a brief introductory session on Indonesian affixes to ensure all students understood the task's context.
Students were then given 40 minutes to write an essay on a familiar topic.
After the essays were collected, the researcher performed a meticulous evaluation to identify morphological errors.
To maintain ecological validity, all procedures were integrated into the school's existing schedule to ensure students performed in a natural academic setting.
Data Analysis Following the interactive analysis model by Miles.
Huberman, and Saldaya .
, the data was processed through three concurrent flows:
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Analysis of Thai Students' Ability in Composing Using Indonesian Affixes in Southern Thailand Data Reduction: Sorting and focusing on specific affixation errors while discarding irrelevant information.
Data Display: Organizing the identified errors into descriptive tables and matrices to visualize frequency patterns.
Conclusion Drawing/Verification: Interpreting the frequency data to explain why certain errors .
, phonological change.
occur frequently among Thai Data Validity To ensure the rigor and trustworthiness of the findings, the study employed triangulation of methods and triangulation of sources.
The results from the writing tests were cross-referenced with classroom observations and teacher interviews (Rahmawati, 2.
This multi-dimensional check ensures that the interpretation of morphological errors aligns with the actual linguistic reality of the students and is supported by existing morphological FINDINGS AND DISCUSSIONS An analysis of essays written by 30 fifth-grade Matayom students at Thamasat Whittaya School indicates that their ability to use Indonesian affixes still faces various morphological challenges.
A total of 25 students made errors in the use of prefixes, suffixes, infixes, confixes, and other affixes, which are linguistically important elements in Indonesian word formation.
This finding is relevant because affixes are morphemic elements that determine the syntactic function and lexical meaning of a word.
Therefore, these errors demonstrate the need for a deeper understanding of the Indonesian affixation system in the context of BIPA learning in Southern Thailand.
This finding is important because affixes function as morpheme elements that determine both the syntactic function and lexical meaning of words in Indonesian grammar.
Therefore, the presence of these errors highlights the need for a more comprehensive understanding of the Indonesian affixation system, particularly in the context of teaching Indonesian as a foreign language in Southern Thailand.
Strengthening teaching in this area is essential to support learners in developing better linguistic competencies and producing more accurate and meaningful written texts.
Table 1.
Frequency of Errors in the Use of Indonesian Affixes in Matayom 5 Students (N = .
Student Name Faisol Masan Affixes prefiks .
er-) Affix Error Burung itu tekurung di Correct Form Burung itu terkurung di Naccawat La-mao infiks (-em-) Anak itu semembunyi di belakang rumah Anak itu bersembunyi di belakang rumah Phokpong Khankham sufiks (Ae.
Adik mencuci-i piring Adik mencuci piring Muhammaddasri Sa-i sufiks (Aea.
Saya membeli minumanan Saya membeli minuman Yusup Sakula infiks .
l-) Abang gelempar bola Abang melempar bola Wiraphat Fanfa prefiks .
er-) Murid bedoakan sebelum Murid berdoa sebelum Phokpong Penjan konfiks .
Buku itu diletakkankan atas Buku itu diletakkan atas Phuripat Roaddoun prefiks .
er-) Adik tesenyum kepada guru Adik tersenyum kepada Worrawat Lawan prefiks .
er-) Saya lari setiap pagi untuk menjaga kesehatan Saya berlari setiap pagi untuk menjaga kesehatan A 2021 The Author.
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Analysis of Thai Students' Ability in Composing Using Indonesian Affixes in Southern Thailand Alawee Yamacharoen prefiks .
e-) Siswa sedang menbaca cerita Badrun Yeesama-ae sufiks (Ae.
Guru mengajari-i siswa Siswa sedang membaca Guru mengajari siswa Sofa Thaipraksa sufiks (Aea.
Nenek memasakkan-kan sup Nenek memasakkan sup Rattana Chaiykhaotong prefiks .
er-) Kami bejalan-jalanan sore Kami berjalan-jalan sore Nisreen Mattala konfiks .
er-Aa.
Besok ada pertemuan-an Besok ada pertemuan Silinna wansu konfiks .
e-Aa.
Guru menilai petulisanan Guru menilai penulisan Sarina Yala konfiks .
e-Aa.
Siswa pengumpulanan tugas dilakukan besok Siswa pengumpulan tugas dilakukan besok Tanasda Ongsara konfiks .
e-Aka.
Siswa menuliskan-kan Siswa menuliskan Nadeeya Saethong konfiks .
er-Aa.
Kami mulai perjalananan pukul tujuh Kami mulai perjalanan pukul tujuh.
Maryam Panwan prefiks .
er-) Anak-anak bermainkan layang-layang Anak-anak bermain layang-layang Firhana Hahyeebilang prefiks .
er-) Adik belarik ke taman Adik berlari ke taman Rusnee Nuydech prefiks .
er-) Nenek tedudukkan di kursi Nenek terduduk di kursi Malisa Jeennui prefiks .
e-) Kakak mefotokan temannya Saitun Inman konfiks .
e-A-.
Ayah meperbaiki-i pintu Kakak memfoto Ayah memperbaiki pintu Sukat Usoh konfiks .
e-Aa.
Nenek mencatat pembelianan Nenek mencatat pembelian barang Sasina Sani sufiks (-a.
Saya membeli makan pedas Saya membeli makanan pedas itu Table 2.
Correct Use of Indonesian Affixes by Matayom 5 Students (N = .
Student Name Affixes Correct Form Origin Word Kuoanbas Saradi prefiks .
e-) Siswa Thailand menuliskan pengalaman mereka saat mengikuti kegiatan budaya Indonesia Muhammadreeyal Akem konfiks .
e- / a.
Guru menjelaskan pelajaran bahasa Indonesia dengan contoh imbuhan yang mudah dipahami Taskeem Danden prefiks .
i-) Cerita yang dibaca siswa sangat menarik dan membantu mereka memahami struktur kalimat Theeraphat Wijit prefiks .
er-) Kelas mereka tampak berhias dengan berbagai poster bertuliskan kosakata Bahasa Indonesia Nabin Khotchawet konfiks .
e- / a.
Sekolah mengadakan pelatihan menulis karangan untuk meningkatkan kemampuan siswa A 2021 The Author.
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Analysis of Thai Students' Ability in Composing Using Indonesian Affixes in Southern Thailand The results of this study were obtained from an analysis of 30 essays by fifth-grade Matayom students .
quivalent to eleventh-grade high school in Indonesi.
at Thamasat Whittaya School.
Southern Thailand.
The most common error found was the inaccurate use of affixes, found in 25 of the 30 students.
The results of this study were obtained from an analysis of 30 essays by fifth-grade Matayom students .
quivalent to eleventh-grade high school in Indonesi.
at Thamasat Whittaya School.
Southern Thailand.
The analysis focused on four types of affixes in Indonesian: prefixes, suffixes, infixes, and confixes.
Each essay was examined to identify 25 errors in affix usage and 5 errors in correcting them according to Indonesian morphological Table 3.
Distribution and percentage of student errors Type of Error Prefiks Sufiks Konfiks Infiks Jumlah Amount Percentage Prefix-Affix Errors The most common type of error was the use of prefix-affixes, occurring at 40%.
These errors included the incorrect use of the prefixes me-, ber-, and ter-.
Some students wrote words with prefix forms that did not conform to phonological rules, such as "memcuci" .
Furthermore, structural errors were also found, such as the use of double prefixes, such as "makan-kan" .
ooking-ka.
, which should be used as "makankan.
" These findings indicate that students still struggle to understand the process of phoneme fusion and the rules of phonological change in Indonesian prefixes.
Suffix-Affix Errors The use of suffix-affix errors was also lower at 20%, particularly the suffixes -kan, -i, and -an.
Some students overused suffixes, such as "jari-i" .
Other errors occurred because students added suffixes to words that do not require them, such as "jari-i" .
or "jalan-an" .
treet-a.
which should be used as "jalan".
This indicates that students do not yet fully understand the function of suffixes in forming word meaning.
Infix Affix (Infixatio.
Errors Incorrect use of infix affixes (-el-, -em-, -in-) occurred at a low rate of 8%, but was still considered significant.
This error was seen when some students mistakenly identified forms such as masukin and tutupin as the result of infixation, even though both forms are uses of non-standard suffixes.
This finding indicates that students are not yet fully able to differentiate the process of infixation from the process of suffixation.
Overall, students need a deeper and more systematic understanding of the characteristics and use of infix affixes in Indonesian Confix Affix Errors (Combination of Prefixes and Suffixe.
Incorrect use of confixes .
e-A-an, pe-A-an, per-A-an, di-A-ka.
was also found at a fairly high rate, at 32%.
A common error was the addition of double suffixes, such as in writing, traveling, or being placed.
This type of error indicates that students know the general confix pattern, but do not yet understand that the suffix in the confix does not need to be added again with the suffix -an.
In addition, some students choose the wrong confix, for example perjalanan-an.
Peraturan-an when it should be perjalanan and Peraturan.
Discussion The research results indicate that students at Thamasat Whittaya School also face the same difficulties as those found in previous studies.
This aligns with research (Sulastri 2.
, which states that affix usage errors found in students' writing are not only identified but also analyzed in depth to understand the patterns and characteristics that emerge.
This analysis indicates that the types of errors occurring reflect students' inability to master basic affixation concepts, such as determining base forms, selecting appropriate affixes, and applying morphophonemic rules.
These findings provide a clearer picture of the linguistic challenges students face, particularly when they must integrate morphological understanding with effective and effective writing skills.
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Analysis of Thai Students' Ability in Composing Using Indonesian Affixes in Southern Thailand Furthermore, several factors contribute to the occurrence of these errors.
A lack of understanding of affixation rules is the primary cause, followed by writing skills that still need to be improved, and a lack of guidance or targeted feedback from teachers.
Although there are differences in the dominant types of errors among students, the root of the problem remains closely related to their understanding of morphological rules and the pedagogical aspects of the learning process.
Therefore, a more systematic and intensive learning strategy is needed to ensure students are able to apply the concept of affixation appropriately in real language contexts (Kaso 2.
The dominant affixation errors found among Thamasat Whittaya School students indicate their inability to fully apply morphological rules.
This aligns with research findings (Lina Yuliasari et al.
, which also highlight the complexity of morphological issues.
They even found that: "This study found morphological errors in affixation, reduplication, and compound words among BIPA FIB UB students.
Affixation errors are located in the morphophonemic processes of assimilation, adaptation, and dissimilation.
" (Fernando.
Basuki, and Suryadi 2.
Thus, it can be concluded that morphological problems for nonnative speakers, including Thai students, are not limited to affixation but involve broader word formation processes, such as reduplication and phonological aspects.
An analysis of Thai students' compositions shows that the prefix me- is the most frequently used affix, and almost all the words formed are verbs.
This finding is consistent with research (Asmoko et al.
, which also concluded that "the most frequently used affix is the prefix me-.
And the most productive word class is the verb class.
" This similarity indicates that the prefix me- has the most essential function in forming active sentences in Indonesian, making it dominant among foreign learners.
This similarity indicates that the prefix me- has a very essential function in forming active sentences in Indonesian (Tyas Pratama 2.
Its dominant use by foreign learners indicates that this affix is considered the most easily recognized and most frequently encountered in the linguistic input they receive, both through learning materials and communicative interactions (Afina Aulia et al.
In addition, the prefix me- plays an important role in forming prefixed verbs that indicate the subject's actions or activities, making it a morphological element that is relatively easy to map into the learner's first language These factors make the prefix me- more quickly mastered than other affixes, although a thorough understanding of the morphophonemic rules that govern it remains a challenge for some learners (Laksanti 2.
CONCLUSION
Based on the research findings and discussion, it can be concluded that the morphological ability of Matayom 5 students at Thammasat Whittaya School.
Southern Thailand, in using Indonesian affixes is at a moderate level with a high propensity for error.
The study identified that 83.
3% of the participants struggled with affixation, particularly regarding the complex rules of word formation and phonological changes.
The most dominant type of error was found in the use of prefixes .
%), followed by confixes .
%), suffixes .
%), and infixes .
%).
These errors primarily stem from a lack of understanding of morphophonemic rulesAisuch as phoneme assimilation and deletionAiand the tendency to over-generalize grammatical rules, resulting in redundant "double affixation" like penulisanan.
While the prefix me- is the most frequently and productively used by students to form active verbs, its mastery remains incomplete due to these underlying phonological complexities.
Furthermore, the study reveals that these morphological challenges are deeply influenced by the typological differences between the Thai language, which is isolating, and Indonesian, which is agglutinative.
To improve students' linguistic competence, this study underscores the urgent need for explicit morphological instruction where affixes are taught not as isolated vocabulary, but as a systematic process of meaning and category change.
Additionally, there is a necessity for ongoing contextual practice that moves beyond multiple-choice exercises toward continuous writing tasks that require students to apply affixes in meaningful A 2021 The Author.
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Analysis of Thai Students' Ability in Composing Using Indonesian Affixes in Southern Thailand Finally, the development of BIPA teaching materials specifically tailored to the needs of Thai studentsAiparticularly those addressing common pitfalls in morphophonemic assimilationAiis essential.
By addressing these morphological gaps.
Indonesian language educators in Thailand can better support students in producing grammatically accurate and semantically clear written compositions, ultimately strengthening language diplomacy through BIPA.
REFERENCES