🇯🇵→🇺🇸 CSV Batch Translator (Japanese to English)

This script batch-translates Japanese CSV files into English using the official Google Cloud Translation API.

It recursively scans a source folder, translates both content and headers, and outputs fully translated CSVs while preserving the original folder structure.

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🚀 Features

• ✅ Translates cell content and column headers
• ✅ Only translates Japanese text (skips English)
• ✅ Uses batch requests for efficiency (100 items/request)
• ✅ Handles UTF-8 and Shift-JIS encoded files
• ✅ Preserves original subdirectory structure
• ✅ Logs untranslated (non-Japanese) values

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🛠 Requirements

• Python 3.8+
• Google Cloud Translation API
• uv (optional, for modern Python dependency management)

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📦 Setup

1. Clone this repository or copy the script

git clone <repo-url>
cd translate-csv

2. Create virtual environment using uv (or venv)

uv venv .venv
source .venv/bin/activate

3. Install dependencies

Run uv pip install -r requirements.txt

4. Set up Google Cloud credentials

• Create a Google Cloud Project
• Enable Cloud Translation API
• Create a service account key (JSON)
• Save the key as: google-credentials.json in this project folder

📂 Folder Structure

├── translate.py
├── google-credentials.json
├── japanese_csvs/
│   ├── file1.csv
│   └── nested/
│       └── file2.csv
├── translated_csvs/       # Generated automatically
├── untranslated_cells_log.txt

🧪 Usage

Run the script: python translate.py

Translated CSVs will appear in translated_csvs/, matching the folder layout of the originals.

📝 Output

• Translated CSV files will have:
  • All Japanese content translated to English
  • Column headers translated
• untranslated_cells_log.txt will contain a list of non-Japanese values that were skipped

⚙️ Customization

You can modify the script to:

• Translate other languages by adjusting the is_japanese() function
• Add glossary terms (e.g., always translate "患者" as "Patient")
• Support .xlsx files using openpyxl

📘 License

MIT License – use freely in personal or commercial projects.

🙋 Support

Feel free to open an issue or email the author for help or improvements. Let me know if you'd like to:

• Add a Makefile or shell script for common tasks
• Package it as a CLI (translate-csv --input foo --output bar)
• Include GitHub Actions to lint or test it automatically

Happy translating!