Automate Multilingual Slack Communication (JA ⇄ EN) with Gemini 2.5 Flash

🧠 How it works

This workflow automatically translates messages between Japanese and English inside Slack — perfect for mixed-language teams.
In our real-world use case, our 8-person team includes Arif, an English-speaking teammate from Indonesia, while the rest mainly speak Japanese.

Before using this workflow, our daily chat often included:

• “Can someone translate this for Arif?”
• “I don’t understand what Arif wrote — can someone summarize it in Japanese?”
• “I need to post this announcement in both languages, but I don’t know the English phrasing.”

This workflow fixes that communication gap without forcing anyone to change how they talk.
Built with n8n and Google Gemini 2.5 Flash, it automatically detects the input language, translates to the opposite one, and posts the result in the same thread, keeping every channel clear and contextual.

⚙️ Features

• Unified translation system with three Slack triggers:
  1️⃣ Slash Command /trans – bilingual posts for announcements.
  2️⃣ Mention Trigger @trans – real-time thread translation for team discussions.
  3️⃣ Reaction 🇯🇵 / 🇺🇸 – personal translation view for readers.
• Automatic JA ↔ EN detection and translation via Gemini 2.5 Flash
• 3-second instant ACK to satisfy Slack’s response timeout
• Shared Gemini translation core across all three modes
• Clean thread replies using chat.postMessage

💼 Use Cases

• Global teams – Keep Japanese and English speakers in sync without switching tools.
• Project coordination – Use mentions for mixed-language stand-ups and updates.
• Announcements – Auto-generate bilingual company posts with /trans.
• Cross-cultural communication – Help one-language teammates follow along instantly.

💡 Perfect for

• Global companies with bilingual or multilingual teams
• Startups collaborating across Japan and Southeast Asia
• Developers exploring Slack + Gemini + n8n automation patterns

🧩 Notes

• You can force a specific translation direction (JA→EN or EN→JA) inside the Code node.
• Adjust the system prompt to match tone (“business-polite”, “casual”, etc.).
• Add glossary replacements for consistent terminology.
• If the bot doesn’t respond, ensure your app includes the following scopes:
  app_mentions:read, chat:write, reactions:read, channels:history, and groups:history.
• Always export your workflow with credentials OFF before sharing or publishing.

✨ Powered by

Google Gemini 2.5 Flash × n8n × Slack API
A complete multilingual layer for your workspace — all in one workflow. 🌍