Several AI translators now claim "keigo support". The quality difference between general-purpose tools (Google Translate, DeepL, ChatGPT) and business-specific tools (BizHonyaku, Yarakuzen) is large in practice. This post lists seven criteria for picking the right keigo translator for your team.
1. Default keigo level
Given Please review this document:
- Google: この文書を確認してください (polite, neutral)
- DeepL: この文書をご確認ください (slightly more polite)
- ChatGPT: こちらの文書をご確認いただけますでしょうか (humble + polite)
- BizHonyaku (external setting): ご確認のほど、よろしくお願い申し上げます (with cushion)
2. Context controls
Quality of keigo depends on context. Look for: recipient type (peer / boss / client), document type (email / contract / memo), relationship state (new / ongoing / apology), tone (concise / formal). Google has none. DeepL has glossaries. ChatGPT does it via prompt. BizHonyaku has dropdowns.
3. Double-honorific detection
Phrases like ご確認頂戴いたします and お送りさせていただきました are over-polite errors that Japanese readers spot immediately. Generic tools produce them; a good keigo translator catches them.
4. Glossary / style guide
Can you tell the tool "always use 弊社 instead of 当社"? DeepL Pro and BizHonyaku yes. ChatGPT in a prompt. Google no.
5. File format support
Word, PDF, Excel, PowerPoint upload with formatting preserved. Critical for real business workflows.
6. Security & confidentiality
Three contractual guarantees to check: no training-data use, short log retention, encryption in transit and at rest.
7. Pricing model
Per-character / per-page vs flat subscription. Pick based on actual volume, not perceived volume.
When to use which
Read foreign content casually: Google / DeepL free is fine.
Personal business email: DeepL Pro or ChatGPT Plus.
Team workflow with keigo discipline: A business translator like BizHonyaku — dropdowns beat prompts when 10 people are using the same tool.
Confidential documents: Business plan with the contractual guarantees above, or on-prem deployment.