Translating locale files with an LLM: what broke

Nine locale files, two Claude models. Keys and placeholders survived every time; what broke was plural forms, a code fence around JSON, and word choice.

Mostly yes, if you look only at the structure. Across nine locale files in five formats, neither Claude Sonnet nor Claude Haiku renamed a key, dropped a placeholder or translated an ICU keyword. The failures sat elsewhere. A language with more plural forms than English needs branches the source never had. One model kept wrapping the answer in a Markdown code fence, which turns a valid JSON file into a broken one the moment it is saved. And the wording of the weaker model read like a dictionary, not like an app.

Read the full report on AISkills402: https://aiskills402.com/blog/translate-locale-files-llm