A foreigner who mixes up a verb tense in Japanese gets a pass. A foreigner who uses casual speech with their boss does not. Keigo, the system of formal speech in Japanese, carries more social weight than almost any other part of the grammar, and it's the part machine translation struggles with most.
Why keigo exists
Japanese grammatically marks the relationship between speaker and listener, not just the content of the sentence. The same idea, "to eat," can be expressed as 食べる (casual), 食べます (polite), 召し上がる (honorific, used for someone of higher status), or 頂く (humble, used to lower your own action relative to the listener). English has no grammatical equivalent. The closest we get is choosing between "eat" and "dine," and that doesn't come close to capturing the social information Japanese encodes directly into the verb.
Used with close friends, family, and people younger or equal in status
Taberu? You eating?
Using this with a stranger, a boss, or a customer sounds abrupt at best and disrespectful at worst.
The default for most adult interactions outside close relationships
Tabemasu ka? Will you eat?
This is the -masu/-desu form taught first in most Japanese courses, and it's a safe default in almost any situation where you're unsure which level applies.
Raises the status of the person you're speaking about or to
Meshiagarimasu ka? Will you, an honored guest or superior, eat?
Used for customers, superiors, or anyone in a position you're showing deference to. You never use sonkeigo to describe your own actions.
Lowers your own status relative to the listener
Itadakimasu. I will humbly eat or receive this.
This is the phrase said before meals in Japan, and it illustrates the core logic of humble speech: it describes your own action, deliberately framed as modest, to show respect toward the listener or the situation.
The most common mistake learners make
Mixing sonkeigo and kenjougo, using honorific forms for your own actions, is one of the most common errors among intermediate Japanese learners. Saying 召し上がります to describe yourself eating sounds like you're praising your own actions, which lands as strange or arrogant rather than polite.
| Situation | Expected register |
|---|---|
| Texting a close friend | Casual |
| Talking to a coworker at the same level | Polite |
| Speaking to your manager about their actions | Honorific |
| Describing your own actions to your manager | Humble |
| Customer service interactions | Honorific (toward customer) + humble (about staff) |
Why machine translation struggles here
Translation engines tend to default to polite form (teineigo) when generating Japanese from English, since it's the safest, most common register in their training data. That works fine for general text, but it means translated business emails can come out sounding flatter and less deferential than what a native speaker would actually write in a formal context. If you're translating something where formality genuinely matters, like a message to a client or a job application, it's worth having a native speaker review the tone, not just the grammar.
Translate a phrase and check how the politeness level comes through.
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