If you have ever tried to learn English in Southeast Asia — or if you are a parent watching your child struggle — you have probably noticed that the same mistakes come up again and again.
This is not a coincidence.
Thai, Vietnamese, Filipino, Indonesian, and Malaysian students share remarkably similar challenges with English grammar. The reason is linguistic: the languages spoken across Southeast Asia handle grammar very differently from English. There are no articles in Thai. Vietnamese does not conjugate verbs. Tagalog has a completely different sentence structure. These differences create predictable patterns of error that show up in classrooms from Bangkok to Jakarta.
The good news is that once you know what the mistakes are and why they happen, fixing them becomes much more straightforward.
Here are the five most common English grammar mistakes ESL students in Southeast Asia make — and exactly how to correct them.
Mistake 1: Using the Wrong Article — or No Article at All
What it looks like:
- “I have dog.” (missing article)
- “She is a best student.” (wrong article)
- “Please close window.” (missing the)
Why it happens:
Thai, Vietnamese, Khmer, and most other Southeast Asian languages do not use articles at all. There is no equivalent of a, an, or the in these languages. So when students learn English, they either leave articles out entirely or guess randomly.
How to fix it:
The rule is simpler than most students think. Use a or an when you are talking about something non-specific — one of many. Use the when both the speaker and listener know exactly which one you mean.
- “I saw a dog in the park.” (any dog — not specific)
- “Please close the door.” (we both know which door)
For a vs an, the choice depends on sound, not spelling. Use an before a vowel sound: an apple, an hour, an MBA.
Practice this daily. Every time you read or hear an English sentence, notice which article is used and ask yourself why.
Mistake 2: Mixing Up Present Simple and Present Continuous
What it looks like:
- “I am going to school every day.” (should be present simple)
- “Listen! The birds sing outside.” (should be present continuous)
- “She is knowing the answer.” (present continuous used with stative verb)
Why it happens:
Many Southeast Asian languages use context words — like every day or now — to indicate time, rather than changing the verb form itself. English requires the verb to change, which is an unfamiliar concept.
How to fix it:
Use present simple for habits, routines, facts, and things that are generally true:
- “She walks to school every morning.”
- “Water boils at 100 degrees.”
Use present continuous (am/is/are + verb-ing) for actions happening right now or temporarily:
- “She is walking to school right now.”
- “I am studying for my exam this week.”
The trick is to look for signal words. Every day, always, usually, never → present simple. Now, at the moment, currently, look, listen → present continuous.
Mistake 3: Confusing Prepositions — In, On, At, and To
What it looks like:
- “I will see you in Monday.” (should be on)
- “She lives on Bangkok.” (should be in)
- “The meeting is in 3pm.” (should be at)
- “I go in school every day.” (should be to)
Why it happens:
Most Southeast Asian languages use a single preposition — or none at all — to cover what English splits across four different words. Direct translation almost always produces the wrong preposition.
How to fix it:
Think of it this way:
- In — for large areas, enclosed spaces, months, years, and parts of the day: in Thailand, in the morning, in July
- On — for surfaces, specific days, and dates: on Monday, on the table, on 5th June
- At — for exact times and precise points: at 3pm, at the door, at school
- To — for movement toward a destination: go to school, travel to Singapore
Do not try to memorise every preposition at once. Learn them in categories and practise one category at a time.
Mistake 4: Subject-Verb Agreement Errors
What it looks like:
- “She go to the market every day.” (missing -s)
- “The team are ready.” (team is singular)
- “Each of the students have a book.” (should be has)
Why it happens:
In Thai, Vietnamese, and many other regional languages, verbs do not change based on the subject. He go and they go use exactly the same verb form. In English, the verb must match the subject — particularly in the third person singular (he, she, it).
How to fix it:
The core rule: he, she, and it always add -s or -es to the verb in present simple.
- “He works every day.”
- “She teaches English.”
- “It rains a lot in Bangkok.”
Watch out for tricky cases. Collective nouns like team, family, class, and group are singular in English — “The team is ready”, not “The team are ready.” And each and every always take a singular verb — “Each student has a book.”
Mistake 5: Word Order in Questions
What it looks like:
- “You are going where?” (statement word order used as a question)
- “What she is doing?” (auxiliary verb in wrong position)
- “Why you are late?” (missing inversion)
Why it happens:
In Thai and many Southeast Asian languages, questions are formed by adding a question word or particle at the end of a normal statement — the word order does not change. English requires the word order to invert, which feels unnatural at first.
How to fix it:
English questions follow a specific structure: Question word + auxiliary verb + subject + main verb.
- “Where are you going?”
- “What is she doing?”
- “Why are you late?”
If there is no auxiliary verb in the statement, add do, does, or did:
- “She works here.” → “Where does she work?”
Practise forming questions from statements every day until the inversion becomes automatic.
The Fastest Way to Fix These Mistakes
Understanding a grammar rule and actually using it correctly are two different things. The gap between them is practice.
If you or your child struggles with any of these five areas, the most efficient way to fix them is through focused, interactive practice — not just reading rules from a textbook.
We built a free 4-lesson grammar course on English Explorers that covers every mistake on this list. Each lesson is 15 minutes, fully interactive, and works on any device. Complete all four lessons, pass the final test, and receive a free English Grammar Certificate.
No payment. No account required. Start today: Fix Your English in 4 Lessons — Free Course
Final Thought
These five mistakes are not signs of low ability. They are the natural result of learning a language that works very differently from your mother tongue. Every student who has mastered English fluency has worked through exactly these challenges.
The difference between students who improve quickly and those who stay stuck is usually one thing: consistent, targeted practice. Know your mistakes, understand why you make them, and practise the correction until it becomes instinct.
Start with the free course. One lesson a day for four days. That is all it takes to begin building a grammar foundation that will serve you for life.
English Explorers is a teacher-built ESL platform serving Southeast Asian families with students aged 4–17. Our courses are designed by certified Cambridge Primary English teachers based in Bangkok, Thailand.