Japanese → Vietnamese
Vietnamese uses 35 sounds. You already own 15 of them from Japanese. The other 20 are the work — and 19 of those are the dangerous kind: close enough to something you already say that you will substitute them without hearing yourself do it.
The silent swaps
Your mouth has something close enough to reach for. These survive for years precisely because they sound right to you — the fix is hearing the difference first, not trying harder.
the move: close, but not identical
Vietnamese: to eat · written "ă", "a (in ay, au)"
A SHORT a. Written ă on its own, but the a of tay and sáu is this vowel too — which is why tai/tay and sao/sáu are different words.
Your /a/ is the one in あさ asa (morning).
the move: velar → palatal
Vietnamese: hello / goodbye · written "ch", "tr (Hanoi)"
A stop made with the tongue body on the palate; there is no 'sh' after it. Close to Korean ㅈ but tighter and with no hiss. tr merges into it in Hanoi (the south says a retroflex /ʈ/).
Your /k/ is the one in かさ kasa (umbrella).
the move: bilabial → labiodental
Vietnamese: phở (noodle soup) · written "ph"
The missionaries' spelling of /f/. There is no letter f in native words.
Your /ɸ/ is the one in ふゆ fuyu (winter).
the move: palatal → velar
Vietnamese: no; not; zero · written "kh"
German ach, Spanish j — or Korean ㅎ in front of ㅡ (흐), which comes close. không is the word you will say most.
Your /ç/ is the one in ひと hito (person).
the move: close, but not identical
Vietnamese: three; father · written "b"
Implosive: the larynx drops and air is drawn in as the lips open. A plain English b is understood, but sounds foreign. New for Korean speakers too — Korean ㅂ is neither voiced nor implosive.
Your /b/ is the one in ばん ban (evening).
the move: close, but not identical
Vietnamese: to go · written "đ"
The barred đ is the ONLY d-sound in Vietnamese; the unbarred d is /z/ (or /j/ in the south).
Your /d/ is the one in だれ dare (who).
the move: aspirated
Vietnamese: to like · written "th"
th is an aspirated t — never English th. thích rhymes with English 'tick', and th is exactly Korean ㅌ against the plain t of ㄸ; a Korean speaker hears this pair without trying.
Your /t/ is the one in たべる taberu (to eat).
the move: unrounded
Vietnamese: cooked rice; a meal · written "ơ"
Say /o/ and unround the lips — the same horn, same instruction. Close to Korean ㅓ (eo), and to American 'bird' with the r taken out.
Your /o/ is the one in おと oto (sound).
the move: unrounded
Vietnamese: to weigh; a kilo · written "â"
A SHORT ơ: cân is clipped, cơn is held. The vowel of American 'cut', or a short Korean ㅓ.
Your /o/ is the one in おと oto (sound).
the move: rounded
Vietnamese: autumn; to collect · written "u"
Your /ɯ/ is the one in うみ umi (sea).
the move: alveolar → labiodental
Vietnamese: happy, fun · written "v"
Hanoi /v/; the south says /j/, so vui sounds like 'yui'.
Your /z/ is the one in みず mizu (water).
the move: uvular → velar
Vietnamese: delicious · written "ng", "ngh"
English and Korean have this sound only at the end of a syllable (sing, 강); Vietnamese puts it at the start. Say 'sing on', then drop the 'si'. ngh is the same sound before e/ê/i.
Your /ɴ/ is the one in ほん hon (book).
the move: open → open-mid
Vietnamese: mother · written "e"
Open e — French è, the e of American 'bed'. Korean ㅐ as it was before Seoul merged it into ㅔ: Vietnamese still keeps the two apart, so mẹ 'mother' and mê 'to be entranced' are different words.
Your /a/ is the one in あさ asa (morning).
the move: close-mid → open-mid
Vietnamese: to give; for · written "o"
Open o — the vowel of 'law' for an American who keeps caught apart from cot, shorter. Korean has nothing between ㅗ and ㅓ; this sits between them.
Your /o/ is the one in おと oto (sound).
the move: palatal → velar, voiced
Vietnamese: chicken · written "g", "gh"
A voiced fricative, like Spanish g between vowels — softer than English g. gh before e/ê/i.
Your /ç/ is the one in ひと hito (person).
the move: approximant → nasal
Vietnamese: house · written "nh"
Spanish ñ. Also a final: anh, bánh.
Your /j/ is the one in やま yama (mountain).
the move: fricative → lateral
Vietnamese: to do, to make · written "l"
Clear l everywhere; never a final.
Your /z/ is the one in みず mizu (water).
the move: it glides, yours would hold still
Vietnamese: money · written "ia", "iê", "ya", "yê"
One diphthong, spelled ia when nothing follows (kia) and iê when a consonant does (tiền).
Your /i/ is the one in いま ima (now).
Words you may say identically
Two or more Vietnamese sounds landing on one sound of yours. Until the ear separates them, the mouth cannot — which is what the ear trainer is for.
Genuinely new
Nothing in Japanese sits close to these. They sound foreign in your mouth — which is the good news: you can hear that you are not saying them yet.
to buy
ua when final (mua), uô before a consonant (muốn). After q the u belongs to the consonant: qua is /kwa/.
Closest thing you own: — but it glides, yours would hold still, rounded.
Rhythm and pitch
The layer spelling never records, and the one that makes a correct sentence still sound foreign.
| Japanese | Vietnamese | |
|---|---|---|
| Rhythm | Mora-timed | Syllable-timed, one tone per syllable |
| Stress | No stress in the English sense — syllables are not louder or longer, so a Japanese speaker reading English tends to flatten it, and an English speaker reading Japanese tends to hammer syllables that should be even. | No lexical stress. Every syllable carries its own tone and its own full vowel, and none is reduced. What sounds like stress to an English ear is a syllable holding its tone longer or louder for emphasis, and grammatical words (đã, sẽ, được) being said lighter and faster than content words. |
| Pitch | Japanese sits between the tone languages and the stress languages, and gets its own name for it: pitch accent. A word has at most ONE place where the pitch drops, and where that drop falls is part of the word. 箸 hashi (drop after ha) is chopsticks; 橋 hashi (drop after shi) is a bridge; 端 hashi (no drop) is the edge. Unlike Cantonese there is no contour to learn per syllable — only 'where does it fall, if at all'. Tokyo and Osaka disagree about the answer for many words, and both are correct. | lexical tone — pitch changes the word |
What you have that Vietnamese doesn't
16 sounds with no job in Vietnamese. They are not mistakes — but they are where an accent leaks in, because a sound you own is easy to use when a hard one is due.
The honest caveat
This is a prediction from the shape of two sound systems, not a recording of you. It says what your inventory makes likely — it cannot know that your Japanese has a regional variety that already owns one of these, or that you learned Vietnamese from someone whose accent you copied. A teacher listening to you beats it. Use it to know what to listen for.
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