Learn Hardcore Japanese: watasi ha tiisai misu wo simasita.

The character は is usually read “ha” as a syllable (in words like はな “hana”).
When it’s the topic particle, it is always pronounced “wa”.
This is just an irregularity you have to memorize: topic は = pronounced “wa.”

Could I use が instead of は and say 私が小さいミスをしました? What’s the difference?

Yes, 私が小さいミスをしました is grammatically correct, but the nuance changes.

私は小さいミスをしました。
- Neutral, just stating what I did.
- 私 is the topic: “As for me, I made a small mistake.”
私が小さいミスをしました。
- Emphasizes I as the one who made the mistake.
- Feels like answering “Who made the small mistake?” → “I did.”
- Useful when contrasting with others or clarifying responsibility.

In everyday conversation, if you’re just describing what happened, 私は… (or dropping 私 entirely) is more common.

Do I really need to say 私? People often say Japanese drops the subject.

You don’t need 私 here. It’s very natural to say:

小さいミスをしました。
→ “(I) made a small mistake.”

Japanese omits the subject whenever it’s clear from context. In a conversation where you are talking about what you did, 私 is usually understood and omitted.

You would keep 私 when:

You’re contrasting subjects (e.g., 彼は大丈夫でしたが、私は小さいミスをしました。 “He was fine, but I made a small mistake.”)
The subject might be ambiguous without it.
You want to sound a bit more explicit or formal in writing or presentations.

In casual speech, 小さいミスをしました (no 私) is perfectly natural.

What is を doing here? Why do we need it after ミス?

を is the direct object marker. It marks what the verb is acting on.

In 小さいミスをしました:

小さいミス = small mistake
を = marks 小さいミス as the object
しました = did / made

So literally: “(I) did a small mistake.” → “I made a small mistake.”

You generally cannot omit を in standard Japanese when the object is right before the verb like this. Leaving it out (小さいミスしました) sounds casual/sloppy or dialectal; in proper standard Japanese, keep を here.

Why is しました used instead of just する or した?

The verb here is する (“to do”), and it’s being used in the past polite form:

Dictionary form: する (to do)
Polite non-past: します (do / will do)
Polite past: しました (did / have done)

So:

ミスをする = to make a mistake
ミスをしました = I made a mistake (polite, past)

If you want a casual version:

ミスをした。
(Plain past instead of polite past)

So:

しました → polite, past
した → casual, past
する → plain, non-past (do / will do, not “did”)

Why is 小さい placed before ミス? Is that always the word order for adjectives?

Yes. In Japanese, an adjective that directly modifies a noun normally comes before the noun:

小さいミス = small mistake
大きい問題 = big problem
新しい本 = new book

The structure is: [adjective] + [noun].

In this sentence:

小さい = small (an い-adjective)
ミス = mistake (noun)

So 小さいミス is exactly like English “small mistake” in word order. You can’t say ミス小さい to mean “small mistake”; that would be ungrammatical.

Why is ミス written in katakana? Is it different from 間違い (まちがい)?

ミス is a loanword from English “miss” or “mistake,” and loanwords are normally written in katakana.

Nuance:

ミス
- Often used for mistakes in work, sports, performance, etc.
- Sounds slightly lighter / more casual.
- Common in business and everyday speech:
  - ミスをする = make a mistake
  - 入力ミス = input error
間違い（まちがい）
- Native Japanese noun.
- Very common, can be used in most situations.
- 間違いをしました / 間違えました = I made a mistake.

In this sentence, 小さいミスをしました and 小さい間違いをしました are both understandable. ミス sounds a bit more like a small slip-up in a task or process; 間違い is more general.

What exactly does 小さい mean here? Could I also say 小さなミス?

小さい is an い-adjective meaning “small / little.”

小さいミス = small mistake

You can also say:

小さなミス

小さな is the attributive form used only before nouns. Nuance:

小さいミス and 小さなミス both mean “a small mistake.”
小さなミス can sound slightly more literary or stylistically polished, but in many contexts they’re interchangeable.

So:

小さいミスをしました。
小さなミスをしました。

Both are natural and mean essentially the same thing.

How would I say “I made a big mistake” or “I made some small mistakes” using this pattern?

You can modify the adjective or the noun:

“I made a big mistake.”
- 大きなミスをしました。
- 大きいミスをしました。 (also acceptable, but 大きな is very common before ミス)
“I made some small mistakes.”
- 小さいミスをいくつかしました。
  - いくつか = several / some
- 小さいミスを何回かしました。
  - 何回か = a few times

You’re basically keeping the same structure [adjective] + ミスをしました, and adding words like 大きい / 大きな / いくつか / 何回か for nuance.

Where is the word “a” in this sentence? How does Japanese express “a small mistake” vs “the small mistake”?

Japanese doesn’t have articles like “a” or “the.”

小さいミスをしました。
Depending on context, this can be translated as:
- “I made a small mistake.”
- “I made one small mistake.”
- “I made a little mistake.”

Whether it feels like “a” or “the” in English depends entirely on context.

If you need to be explicit:

一つ小さいミスをしました。 = I made one small mistake.
その小さいミスをしました。 = I made that small mistake (referring to a specific one already known in the conversation).

But in most natural Japanese, you just say 小さいミスをしました and let context fill in the “a/the.”

Can I change the word order, like 小さいミスは私がしました? Is that still correct?

Yes, you can change the word order somewhat, but it changes nuance/focus.

Base sentence:

私は小さいミスをしました。
→ Neutral: “I made a small mistake.”

Examples of re-ordering:

小さいミスは私がしました。
- Topic = 小さいミス.
- Emphasis that I am the one who made that small mistake.
- Feels like: “As for the small mistake, I made it.”
小さいミスを私はしました。
- Slight emphasis on 私 as the one who did it.
- Could be contrastive: “I (as opposed to someone else) made a small mistake.”

Japanese allows some word order flexibility because roles are marked by particles (は, を, が), but:

The verb しました usually stays at the end.
The neutral, most common order here is the one you learned:
私は + 小さいミスを + しました。

When should I use 私 vs 僕 or other words for “I” in a sentence like this?

Some common first-person pronouns:

私（わたし）
- Gender-neutral in formal contexts.
- Polite, safe in almost all situations.
- In casual speech, tends to sound feminine or formal.
僕（ぼく）
- Common for males, especially younger men or in casual settings.
- Polite but less formal than 私.
俺（おれ）
- Very casual, masculine, can sound rough depending on context.

In a polite sentence like 小さいミスをしました, you could combine:

私は小さいミスをしました。 (neutral/formal)
僕は小さいミスをしました。 (polite but less formal, male speaker)

In many real conversations, you just say:

小さいミスをしました。
and drop the pronoun altogether if it’s clear you’re talking about yourself.