Thai Lookalike Letters: The Stroke That Tells Them Apart
TL;DR: Five sets of Thai letters are separated by a single stroke: ก ถ ภ, ค ด ต, พ ฟ ผ ฝ, ข ช and บ ป ษ. Reading one as another is rarely one error, because the letters in a set usually sit in different tone classes and take different sounds at the end of a syllable. Three of the five sets turn on the same stroke in the same place, a stem that climbs above the body line, and only four letters in the alphabet have it.
A shape mistake is three mistakes at once
Take ก, ถ and ภ. At a glance they are one letter drawn three ways: the same two uprights, the same width, the same height, and in the outline data the three shapes stay within a few units of each other until the very bottom. What they are not is interchangeable. ก is mid class and reads k at both ends of a syllable. ถ is high class, /tʰ/ at the start and t at the end. ภ is low class, /pʰ/ at the start and p at the end.
So reading ถ where ภ is written gets you the wrong consonant at the front of the word, the wrong consonant at the back of it, and the wrong tone, because the class of the initial consonant is one of the things that decides which of the five tones a syllable carries. That is why these sets deserve their own practice instead of being absorbed as you go: consonant class is doing work you cannot hear until you have already read the letter wrong.
The useful part is that each of these sets has one settled answer. There is a single place to look, and once you know where it is, the pair stops being a pair.
One stroke settles three of the five sets
Pull บ and ป out of the typeface this site and the app render Thai in, Noto Sans Thai, and compare them line by line down the glyph. From the body line to the baseline they are not merely similar, they are the same shape to the unit. The whole difference is that the right-hand stem of ป does not stop at the body line: it carries on 197 units further up, in a letter whose body is 548 units tall.
ผ and ฝ are the same story, identical from the body line down and separated only by that stem on ฝ. พ and ฟ are not quite identical elsewhere, but the difference that matters is again one raised stem, in the same position and at the same height. Three sets, one stroke, always the rightmost upright.
Only four letters in the whole alphabet carry a stroke that reaches that high: ป, ฝ, ฟ and ฬ. Four others end in a small flick that also clears the body line - ฐ, ศ, ส and ฮ - but those rise less than a fifth as far, which is why they do not read as tall. Anything standing well above the line is one of four letters, and two of the four are in this article.
Fifteen letters and the stroke to check in each
Read this by set rather than by row. The point is never the individual letter, it is what separates it from the one it is being confused with.
| Letter | Name | Class | Starts | Ends | The stroke to check |
|---|---|---|---|---|---|
| ก | กอไก่ ko kai | mid | k | k | The left stroke runs down and stops flat on the line |
| ถ | ถอถุง tho thung | high | th | t | The same stroke turns right into a small hook under the middle |
| ภ | ภอสำเภา pho sam-phao | low | ph | p | It turns left instead, out past the left edge of the letter |
| ค | คอควาย kho khwai | low | kh | k | A tooth points right from the left upright, halfway down |
| ด | ดอเด็ก do dek | mid | d | t | One peak, no tooth, and a hook at the foot |
| ต | ตอเต่า to tao | mid | t | t | Two peaks along the top, where ค and ด have one |
| พ | พอพาน pho phan | low | ph | p | Three uprights, none of them raised |
| ฟ | ฟอฟัน fo fan | low | f | p | Three uprights, the last one raised |
| ผ | ผอผึ้ง pho phueng | high | ph | p | Two uprights, neither raised |
| ฝ | ฝอฝา fo fa | high | f | p | Two uprights, the second one raised |
| ข | ขอไข่ kho khai | high | kh | k | The right stroke is a plain stem the whole way down |
| ช | ชอช้าง cho chang | low | ch | t | A tooth bites into that stem from the right, near the top |
| บ | บอใบไม้ bo bai-mai | mid | b | p | Both stems stop at the body line |
| ป | ปอปลา po pla | mid | p | p | The right stem climbs well above it |
| ษ | ษอฤๅษี so rue-si | high | s | t | An arm reaches out to the right, past the bowl |
Two of the fifteen come with a caveat. ษ is rare and shows up mostly in words borrowed from Pali and Sanskrit, ฤๅษี (a hermit) among them, so you will meet it in a name long before you meet it in a sentence. ภ is rarer still and the most work to write in the set, three stacked strokes where ก has two. Neither is a letter to drill early. Both are letters to recognise, which is a lower bar and the one that matters here.
พ ฟ ผ ฝ is a grid, not a list
The four-letter set looks like the worst of the five and is the easiest, because two independent features cover it. Count the uprights: three means low class, two means high class. Then look for the raised stem, which is present on both letters that read /f/ and absent on both that read /pʰ/. Every letter in the set is one answer to each question.
| Uprights | No raised stem | Raised stem |
|---|---|---|
| Three, low class | พ, /pʰ/ | ฟ, /f/ |
| Two, high class | ผ, /pʰ/ | ฝ, /f/ |
That the raised stem lines up with /f/ here is a local accident rather than a rule you can carry elsewhere: ป has the same stroke and reads p. Inside this set it holds, though, and a cue that settles four common letters is worth keeping.
Drill the pair, not the letter
The usual way to practise letters is one at a time: see ฝ, say ฝ. That trains recall, and recall is not what fails on a lookalike. What fails is discrimination, and discrimination only gets practised when both options are on the table at the same moment.
So change the question from what letter is this to which of these two is this. Three passes usually move a set from guesswork to certainty:
- Write the set out, say the differing stroke aloud for each letter, and mark where on the shape it sits.
- Cover the names, point at a letter at random, and say the stroke before the letter.
- Read the set inside real words, where the letter is small and crowded: ปลา, ผม, ฝน, ฟัน.
The third pass is the one people skip and the one that transfers. A letter you can name on a flashcard at full size is not yet a letter you can read at the size it appears in an unspaced line of Thai, where no gap tells you the word has ended.
What survives when the letter is handwritten
Everything above is measured off a printed typeface, and handwriting moves some of the cues. Thai handwriting instruction teaches every consonant as beginning at its head, the small loop the pen makes before the body of the letter, with two exemptions: ก and ธ have no head at all. ก sits in the first set on this page, so the letter you would most like a head to anchor is one of the two that never had one.
The practical upshot is that the top of a handwritten letter is its least reliable part. ข and ช in particular are often written with the top looped differently from the printed form, and a hurried hand deforms the head before it deforms anything structural. What survives is the structure: the raised stem on ป, ฝ and ฟ, the direction the foot of ถ and ภ turns, the second peak on ต, the tooth on ค and ช. The order the strokes go down in explains why the head comes first and what that does to the shape of everything after it.
Where this sits in learning to read
Lookalikes are not a topic you study once. They arrive in the order the letters arrive: ก, ด, ต, บ and ป are among the first letters anyone learns, and their confusable partners turn up several stages later, by which time the early shape has hardened. Meeting ป before ฝ means the raised stem registers as ordinary rather than as the marked case, and that is worth undoing deliberately.
Phayan is an app for learning to read Thai script, and it introduces the letters one at a time from zero rather than handing over a chart to memorise. Where a letter has a confusable partner, the comparison travels with it, so ถ arrives with the note about ภ attached instead of as a shape on its own. Every word in it has audio, and progress is kept on the device without an account, so the sets above are something you can go and test yourself on straight away.
Frequently asked questions
What is the best way to learn Thai letters that look the same?
Practise the pair together rather than each letter alone, because what fails on a lookalike is telling two shapes apart, not remembering one of them. Say the differing stroke out loud before you name the letter, then read both letters inside real words at normal size. An Anki deck with one letter per card trains the wrong thing here, since every card has only one plausible answer and the discrimination never gets tested. Phayan attaches the comparison to the letter itself, so a letter with a confusable partner is not taught as a shape on its own.
How do I tell ผ and ฝ apart?
The second upright of ฝ carries on well above the body line and the second upright of ผ stops at it. In the typeface Phayan renders Thai in, that raised stem is the only difference between the two shapes: from the body line down to the baseline the outlines match to the unit. Both letters are high class, so the tone behaviour is identical and only the consonant changes, ผ being /pʰ/ and ฝ being /f/. The same stroke in the same place separates บ from ป and พ from ฟ, which is three pairs for the price of one cue.
Is it worth learning the rare lookalikes like ษ and ภ?
Worth recognising, not worth drilling. ษ turns up mostly in words taken from Pali and Sanskrit and ภ is rare enough that most learners meet it first inside a name, so neither repays the practice time that ก or ต does. The reason to know them anyway is that each sits in a set with a very common letter, so the cost of not knowing them lands on บ and ก rather than on themselves. Phayan holds the rare letters back to a later stage and teaches them as recognition, which is a lower bar than production and the right one here. ThaiPod101 and similar course libraries tend to present the consonant inventory in one lesson, which puts the rare letters and the everyday ones on the same footing.
What is the difference between ข and ช?
One tooth. The two letters share their left side and their height, and ช has a small tooth biting into its right-hand stem from the right, near the top, where ข keeps a plain stem all the way down. The consequences are much larger than the shape: ข is high class and reads /kʰ/ at the start of a syllable and k at the end, while ช is low class and reads /tɕʰ/ at the start and t at the end, so the pair differ in class, in initial sound and in final sound. Phayan introduces them several stages apart for that reason, with the comparison attached to whichever one you meet second.
Do Thai readers ever mix these letters up?
Not while reading, for the same reason a fluent English reader does not stop to distinguish b from d: whole words are taken in at once and the surrounding letters settle any ambiguity long before the shape has to. It shows up in handwriting instead, which is part of why the printed and handwritten forms of ข and ช diverge at the top. For a learner the asymmetry is the useful bit, because it means the fix is more exposure to real words rather than more time spent on the letters in isolation. Phayan builds that exposure from the first lesson, with audio on every word and no account needed to start.