Why expertise disappears in a second language
Expertise is expressed through precision: the right term rather than the approximate one, the qualification that marks where a claim stops, the aside that shows you know the exceptions. All of that is expensive in a second language and all of it is dropped first under load.
What remains is the content without the markers of expertise, which is why specialists often feel they sound naive in Japanese. The knowledge is intact; the signals are missing.
The encouraging part is that the signals can be replaced with cheaper ones. Explicit structure, defined terms and numbered points read as competence, and all three are available at a much lower level of Japanese than nuance is.
Specialist vocabulary is smaller than you think
Technical vocabulary feels intimidating and is usually easier to acquire than general vocabulary, because it is a closed set. A few hundred terms cover most of what is said in a given field, they recur constantly, and the context is shared with your listener.
A large proportion is also katakana English, which means the work is learning the Japanese pronunciation of a word you already know rather than learning a new word at all.
| Japanese | Romaji | Meaning |
|---|---|---|
| リスクを評価します。 | Risuku o hyōka shimasu. | We assess the risk. |
| 仕様を確認してください。 | Shiyō o kakunin shite kudasai. | Please check the specification. |
| 納期はいつになりますか。 | Nōki wa itsu ni narimasu ka. | When is the delivery deadline? |
| この工程に問題があります。 | Kono kōtei ni mondai ga arimasu. | There is a problem in this process. |
| データを共有します。 | Dēta o kyōyū shimasu. | I will share the data. |
| 前提条件が違います。 | Zentei jōken ga chigaimasu. | The assumptions are different. |
Get these from material your field actually uses in Japanese rather than from a dictionary. A dictionary gives you a correct word; practitioners use a specific one.
Explaining simply without patronising
Simplifying an explanation is a skill in any language and it is not the same as dumbing it down. The technique is to give the shape first, then one concrete example, then the qualification, and to define any term the moment you use it.
Learners often resist this because it feels like conceding that their Japanese is limited. In fact it is what good explanation looks like in any language, and it usually improves the explanation.
- State the purpose before the mechanism: what it is for, then how it works.
- Give one concrete example immediately; abstraction alone loses people.
- Define each term as you introduce it, in one clause.
- Number your points and say how many there are before you start.
- Check understanding at each boundary rather than at the end.
The phrases that carry an explanation
A small set of framing phrases does most of the structural work, and they are worth making automatic because they buy thinking time as well as signalling structure.
Checking understanding as you go is particularly useful for a learner, since it catches the moment where your Japanese, rather than the content, lost them.
| Japanese | Romaji | Meaning |
|---|---|---|
| 簡単に言うと、こういうことです。 | Kantan ni iu to, kō iu koto desu. | Put simply, it is like this. |
| 専門用語で言うと、 | Senmon yōgo de iu to, | In technical terms, |
| 例を挙げると、分かりやすいと思います。 | Rei o ageru to, wakariyasui to omoimasu. | An example will make it clearer. |
| ここまでは大丈夫でしょうか。 | Koko made wa daijōbu deshō ka. | Is everything clear so far? |
| 細かいところは省きますが、 | Komakai tokoro wa habukimasu ga, | I will skip the details, but |
| 正確に言うと少し違いますが、 | Seikaku ni iu to sukoshi chigaimasu ga, | Strictly speaking it is slightly different, but |
When your Japanese is behind your seniority
A specific discomfort arises when your position is senior and your Japanese is not. Instructions come out blunter than intended, disagreement is hard to soften, and the mismatch is visible to everyone in the room.
The practical answer is to be explicit about the gap once, early, rather than letting it be inferred repeatedly. It costs one sentence and it changes how everything afterwards is read.
| Japanese | Romaji | Meaning |
|---|---|---|
| 日本語がまだ十分ではないので、失礼があったらすみません。 | Nihongo ga mada jūbun de wa nai node, shitsurei ga attara sumimasen. | My Japanese is not yet sufficient, so I apologise if I am impolite. |
| 言い方がきつく聞こえたら、教えてください。 | Iikata ga kitsuku kikoetara, oshiete kudasai. | If my phrasing sounds harsh, please tell me. |
| 技術的な話は英語でもいいですか。 | Gijutsuteki na hanashi wa eigo demo ii desu ka. | May I use English for the technical parts? |
| 確認しながら進めさせてください。 | Kakunin shinagara susumesasete kudasai. | Let me proceed while confirming as we go. |
| 書面でも共有します。 | Shomen demo kyōyū shimasu. | I will also share it in writing. |
| 意見があれば、遠慮なく言ってください。 | Iken ga areba, enryo naku itte kudasai. | If you have views, please say so freely. |
Sharing decisions in writing as well as speaking is worth doing regardless. It removes the risk that a softened instruction was heard as optional.
Preparing the three explanations you give most
Almost everyone in a specialist role gives the same three explanations repeatedly: what they do, what their team does, and the one concept that outsiders always ask about. Preparing those three properly covers a surprising proportion of your professional speaking.
Prepare each at two lengths, three sentences and one, because the situation decides which you need and composing the short version on the spot is harder than the long one.
The half you cannot prepare is the follow-up question, which is where an explanation is actually tested. Explaining your field to an AI Sensei in Unihongo's immersive 3D classroom supplies exactly that, since it will ask the obvious outsider question you have stopped noticing, and the session report shows which parts of the explanation collapsed under it.
Rehearse the one-sentence version most. It is the one you will need at a party, in a lift, and every time someone asks what you do.