How to Say 'I Don't Understand' in Japanese: 15 Natural Phrases (With Pronunciation)

The Short Answer

The most common way to say "I don't understand" in Japanese is わかりません (wah-kah-ree-mah-SEN). It is polite, widely used, and safe with strangers, teachers, and customer service. With friends, you will hear わからない (wah-kah-rah-NYE) or the softer casual わかんない (wah-kahn-NYE).

Japanese is spoken by about 123 million people worldwide, according to Ethnologue (2024). Most of those speakers are in Japan, but you will also meet Japanese speakers in communities across North America, South America, Europe, and Oceania, which means these phrases show up far beyond tourism.

If you want a broader foundation for everyday interactions, pair this guide with how to say hello in Japanese and how to say goodbye in Japanese.

Why "I don't understand" is a politeness skill in Japanese

In many languages, "I don't understand" is purely informational. In Japanese, it also manages the relationship, because it can imply "you explained badly" if you say it too bluntly.

This is where politeness strategies matter. Haruo Shirane’s work on Japanese language and culture is often used in university settings to show how social context shapes expression choices, especially around formality and indirectness. You do not need to overthink it, but you do want a few "softeners" ready.

わかりません

わかりません (wah-kah-ree-mah-SEN) is the standard polite "I don't understand." It comes from the verb 分かる (わかる, wah-kah-roo), meaning "to understand."

Use it when you want to sound respectful but not overly formal. It works in shops, on trains, at hotels, and in class.

When it can sound too final

By itself, わかりません can end the conversation if your tone is flat. In real speech, people often add a follow-up request, even a tiny one, to show cooperation.

Good add-ons include "one more time," "slowly," or "what does that mean?"

わからない

わからない (wah-kah-rah-NYE) is the casual version. It is common with friends, siblings, and classmates you are close to.

With strangers, it can sound blunt, especially if you are being helped by staff. If you are unsure, switch back to わかりません.

わかんない

わかんない (wah-kahn-NYE) is a very common conversational contraction of わからない. It often sounds less sharp than わからない because it feels more like thinking out loud.

It is best treated as casual slang. Use it with friends, not in formal settings.

よくわかりません

よくわかりません (yoh-koo wah-kah-ree-mah-SEN) means "I don't really understand" or "I don't understand well." よく here means "well" or "clearly."

This is a great phrase when you understood some parts but not the whole message. It sounds cooperative and avoids the harshness of a hard no.

それはどういう意味ですか

それはどういう意味ですか (soh-reh wah doh-yoo ee-MEE dehss-kah) means "What does that mean?" It is one of the most useful follow-ups after "I don't understand."

It works for vocabulary, idioms, and even implied meaning, like when someone is being indirect.

もう一度お願いします

もう一度お願いします (moh-eh-chee-doh oh-neh-GAH-ee-shee-mahss) is the polite, all-purpose "One more time, please." It is perfect after わかりません.

You will hear it constantly in real life, including when native speakers did not catch something due to noise.

ゆっくりお願いします

ゆっくりお願いします (yook-KOO-ree oh-neh-GAH-ee-shee-mahss) means "Slowly, please." It is often more helpful than repetition, because the issue is usually speed, not vocabulary.

Use it with staff, taxi drivers, and anyone giving directions.

A natural combo

A very natural sequence is: すみません + わかりません + ゆっくりお願いします. It sounds like a learner who is trying, not someone who is refusing.

知りません

知りません (shee-ree-mah-SEN) means "I don't know" in the sense of "I do not have that information." It comes from 知る (しる, shee-roo), "to know."

Learners often overuse わかりません when the situation is actually about knowledge, not comprehension. Kenkyusha dictionary entries for 分かる and 知る are useful for seeing this distinction in typical usage examples.

Quick distinction you can apply immediately

• If you did not catch the explanation: わかりません.
• If you never knew the answer: 知りません.

Choosing the right level: casual, polite, and formal

Japanese has multiple politeness levels, and "not understanding" sits right in the middle of them. The Agency for Cultural Affairs publishes guidance on polite language (敬語, keigo) and how it functions in public life, and the key takeaway for learners is simple: match the situation, not your mood.

Casual: friends and peers

Use:

• わからない (wah-kah-rah-NYE)
• わかんない (wah-kahn-NYE)
• どういう意味？ (doh-yoo ee-MEE)

Polite: strangers, service, teachers

Use:

• わかりません (wah-kah-ree-mah-SEN)
• よくわかりません (yoh-koo wah-kah-ree-mah-SEN)
• もう一度お願いします (moh-eh-chee-doh oh-neh-GAH-ee-shee-mahss)

Formal: workplace and high-stakes situations

You can go more formal with patterns like:

• 理解できません (ree-KYE deh-kee-mah-SEN, "I cannot understand")
• 恐れ入りますが (oh-soh-reh ee-ree-mahss gah, "I am sorry, but...")

These are correct, but many learners sound more natural by staying in polite speech and adding softeners.

Real-life scripts you can copy

Memorizing single phrases helps, but scripts help more because they include the follow-up that keeps the conversation moving.

In a restaurant

• すみません、わかりません。おすすめは何ですか。
  (soo-mee-mah-SEN, wah-kah-ree-mah-SEN. oh-soo-soo-meh wah nahn dehss-kah)
  "Sorry, I don't understand. What do you recommend?"

If you want more restaurant-ready lines, see at the restaurant in Japanese.

When getting directions

• すみません、もう一度お願いします。ゆっくりお願いします。
  (soo-mee-mah-SEN, moh-eh-chee-doh oh-neh-GAH-ee-shee-mahss. yook-KOO-ree oh-neh-GAH-ee-shee-mahss)

This is polite, clear, and usually gets you a slower rephrase.

In a Japanese class

• すみません、そこがよくわかりません。例をもう一つお願いします。
  (soo-mee-mah-SEN, soh-koh gah yoh-koo wah-kah-ree-mah-SEN. reh-eh oh moh-eh hee-toh-tsoo oh-neh-GAH-ee-shee-mahss)
  "Sorry, I don't understand that part well. One more example, please."

The Japan Foundation’s learning materials emphasize classroom language like asking for repetition and examples, because it keeps you engaged even when you are lost.

Common mistakes learners make (and the fixes)

Mistake 1: repeating わかりません without asking for help

If you only say "I don't understand," the other person has to guess what you need. Ask for one concrete action: repeat, slow down, or explain meaning.

Better:

• わかりません。もう一度お願いします.
• よくわかりません。ゆっくりお願いします.

Mistake 2: using 知りません when you mean comprehension

If someone explains a process and you say 知りません, it can sound like "I have no idea about that topic," not "I did not catch what you said."

Fix:

• Use わかりません for comprehension.
• Use 知りません for factual knowledge.

Mistake 3: sounding too direct in tense moments

When you are stressed, you might default to a short わからない. In Japanese, short direct negatives can feel sharp.

Fix:

• Add すみません or ちょっと.
• Use よくわかりません instead of a hard no.

How movies and TV make these phrases stick

"I don't understand" phrases are high-frequency in dialogue because characters mishear, misunderstand, or ask for clarification. That repetition is exactly what you want as a learner.

If you are learning through clips, focus on:

• The phrase itself (わかんない vs わからない vs わかりません)
• The follow-up request (もう一度, ゆっくり)
• The relationship cues (friends vs boss vs stranger)

For more context-heavy Japanese learning, browse the Wordy blog and compare how greetings and closings shift by situation in how to say hello in Japanese and how to say goodbye in Japanese.

When "I don't understand" is not about language

Sometimes you understand the words, but not the social meaning. Japanese can be indirect, especially around refusals, criticism, and requests.

If you suspect hidden meaning, try:

• つまり、こういうことですか。
  (tsoo-mah-ree, kohh-yoo kohh-toh dehss-kah)
  "So, do you mean this?"

This invites confirmation without accusing the other person of being unclear.

A quick note on staying safe with tone

When people are frustrated, they sometimes reach for stronger language. If you are tempted to copy what you hear in edgy scenes, pause and remember that swearing is highly context-dependent in Japanese.

If you are curious, keep it separate from your daily speaking practice and read our guide to Japanese swear words as cultural knowledge, not as a starter pack.

Practice plan: learn these in 10 minutes

1. Memorize the polite base: わかりません.
2. Add one repair request: もう一度お願いします.
3. Add one speed request: ゆっくりお願いします.
4. Add one meaning question: それはどういう意味ですか.
5. Learn the casual pair for friends: わからない and わかんない.

Once these are automatic, you will stop freezing when you miss something, and you will start steering the conversation.

Wrap-up

Use わかりません (wah-kah-ree-mah-SEN) as your default "I don't understand" in Japanese, then immediately follow it with a helpful request like もう一度お願いします (moh-eh-chee-doh oh-neh-GAH-ee-shee-mahss) or ゆっくりお願いします (yook-KOO-ree oh-neh-GAH-ee-shee-mahss). With friends, わからない (wah-kah-rah-NYE) and わかんない (wah-kahn-NYE) will sound more natural.

If you want more high-frequency phrases that appear constantly in dialogue, add how to say I love you in Japanese to your list, because it teaches the same skill: choosing tone based on relationship.