Lessons from Building a Translator App That Beats Google Translate and DeepL

Summary

How It Started Recently, I made a new app called Kintoun. It’s a document translator that delivers very high quality translations and keeps the original layout almost perfectly. At first, I didn’t expect much. But after comparing it with Google Translate and DeepL, I was surprised to see that my app actually performs better in many cases. In this post, I want to share what I’ve learned while building it. Writing helps me organize my thoughts, and maybe some of this will be useful if you’re working on your own project too. Lesson #1. Surprise: My app is actually better than Google Translate and DeepL Let me show you some examples. Document #1: Original This is a Word document from Microsoft: Download this file (docx) Document #1: Google Translate Result I translated it into Japanese using Google Translate: Download this file (docx) Google Translate couldn’t handle it well. The text wasn’t translated, and the layout and fonts got messed up. I tried with different documents and languages, and it was always the same. Document #1: DeepL Result Now let’s try DeepL: Download this file (docx) DeepL did a much better job, but some parts, like “Appetizer,” were missing. Document #1: Kintoun Result Finally, here is the result from Kintoun: Download the file (docx). Kintoun correctly translated all the text and kept the layout intact. Document #2: Original Sometimes documents have Phonetic Guide Text (also called Ruby text) to show pronunciation. For example, Japanese documents often include Hiragana above Kanji. Here is another document with phonetic guides: Download the file (docx) Document #2: Google Translate Result I translated it into Japanese using Google Translate: Download the file (docx) Google Translate completely ignored the text with phonetic guides. The translation became incomplete and confusing. Document #2: DeepL Result Here is the result from DeepL: Download the file (docx) DeepL could handle the phonetic guides, but it broke the layout. For example, the bulle...