Interjections & Fillers: ano〜・eto〜・sou desu ne (the little words that make conversation natural) [JLPT N4]
Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026
Master interjections and fillers to make your Japanese conversation more natural and smooth.
「あっ、えーと、そうですね…」 — the little words that make talk natural
Japanese speech is full of 「あっ」「へえ」「えーと」「なるほど」 — these interjections (expressing emotion: surprise, realization) and fillers (buying thinking time: えーと, あの…) aren't “formal grammar,” but they're key to making conversation sound natural, not stiff. This guide gathers the most common interjections and fillers, teaching you to drop the right little word at the right moment so your Japanese sounds more native.
Two types: interjections vs fillers
- Interjections = express in-the-moment emotion／reaction: あっ (noticing, oops), へえ (oh, I see／surprise), えっ (huh?／didn't catch it), うわー (whoa), なるほど (I see, understood).
- Fillers = buy thinking time／soften: えーと／ええと (um…), あの／あのう (uh…), なんか (like…), まあ (well…).
Interjections are “reactions,” fillers are “stalling／softening.”
Common interjections & fillers
| Word | Type／nuance | Use |
|---|---|---|
| あっ | interjection (noticing, oops) | あっ、忘れた！ （Ah, I forgot!） |
| へえ | interjection (oh, surprise) | へえ、そうなんだ |
| えっ | interjection (huh?, surprise) | えっ、本当？ （Huh, really?） |
| えーと／あの | filler (let me think) | えーと、次は… |
See it in context
- あっ！財布を家に忘れてきた！(Oh! I left my wallet at home!) — noticing, oops
- へえ、彼女が結婚するんだ。(Oh, she's getting married.) — surprise, I see
- えっ、そうなんですか？(Huh, is that so?) — surprise
- えーと、なんて言えばいいかな。(Um… how should I put it.) — buying time
- なるほど、わかりました。(I see, got it.) — understanding, agreement
⚠️ Common mistakes to avoid
① Don't overuse fillers in formal settings. In interviews or presentations, a stream of “えーと, あのー” sounds unsure and unprepared. A brief pause beats constant “えーと.”
② あっ vs えっ. あっ = you notice／remember (あっ、忘れた); えっ = surprise at what someone said／didn't catch it (えっ、本当？). Different directions.
③ Mind the tone of 「へえ」. 「へえ」 shows surprise/admiration (へえ、すごい); but a flat 「へえ…」 can sound dismissive or uninterested — careful with seniors.
🔄 Compare: あっ／えっ／へえ／なるほど
| Form | Nuance | When |
|---|---|---|
| あっ | noticing yourself, oops | remembering, realizing |
| えっ | surprise, didn't catch | startled by what they said |
| へえ | oh, I see, admiration | hearing new info |
| なるほど | understanding, agreement | after grasping the point |
💡 Quick takeaway
Textbooks rarely teach these, but they're key to “sounding Japanese” — a well-timed 「へえ！」「なるほど」「えーと…」 makes you feel natural and engaged. The best way to learn them is to imitate dramas and variety shows: notice which one Japanese people use in which situation. One caution: go easy on fillers in formal settings (interviews, presentations) — nonstop “えーと, あのー” reads as nervous and unprepared. Let loose casually, rein it in formally.
❓ Questions you might have
Q: 「あっ」 vs 「えっ」?
Different directions: 「あっ」 is you noticing/remembering (あっ、鍵を忘れた = oh, I forgot my keys); 「えっ」 is surprise at what someone else said, or not catching it (えっ、今なんて？ = huh, what did you say?). One points inward (self-realization), the other outward (reacting to others).
Q: Should I use fillers (えーと, あの)?
In casual talk, moderate use is natural — it buys thinking time and softens. But go easy in formal settings (interviews, presentations, with clients) — a stream of “えーと, あのー” reads as nervous and unprepared. Practice “a short pause instead of a filler” and you'll sound more professional.
🖊️ Practice Questions (5)
Q1. 「___！財布を忘れた！」(Ah! I forgot my wallet! — a sudden realization)
(A) へえ (B) あっ (C) ふーん (D) えーと
Q2. 「___、彼女が結婚するって？信じられない！」(Huh?! She's getting married? — surprise)
(A) ふーん (B) へえ (C) えっ (D) うわ
Q3. 「___、そうなんですね。知りませんでした。」(Oh, I see. I didn't know that — gaining new information)
(A) えーと (B) へえ (C) あのー (D) うわ
Q4. 「フィラー」とは何か？
(B) 会話の間を埋め、思考時間を稼ぐための語（えーと・あのーなど）。
(C) 男性だけが使う語。
(D) 否定を表す語。
Q5. 「___、なんて言えばいいかな……そうですね、少し難しいです。」(Um, how should I put it... well, it's a bit difficult — a filler / hesitation)
(A) うわ (B) あのー (C) まじで (D) へえ
Answer Explanations
1. (B) あっ ── 「あっ！財布を忘れた」(Ah! I forgot my wallet!) = a sudden small realization → あ/あっ (mild surprise / sudden realization).
2. (C) えっ ── 「えっ！彼女が結婚するって？」(Huh?! She's getting married?), 「信じられない」(can't believe it) = surprise / astonishment → えっ (moderate-to-high surprise / disbelief).
3. (B) へえ ── 「へえ、そうなんですね」(Oh, I see), 「知りませんでした」(I didn't know) = an interjection on gaining new information → へえ (I see / is that so).
4. (B) ── フィラー = a filler, a word inserted into gaps in speech to buy time to think (えーと・あのー・そうですね, etc.); not an exclamation, but a tool for smoothly connecting conversation.
5. (B) あのー ── 「あのー」(um), 「なんて言えばいいかな」(how should I put it) = hesitation / filling a gap → あのー (a filler, used when hesitating / about to start speaking).