ICU Message Format

ICU Message Format is part of the International Components for Unicode (ICU) suite. It is widely used in localization to create dynamic, context-aware messages that adapt to grammatical and structural rules across languages. Instead of hardcoding separate strings for each scenario, developers use ICU Message Format to define templates that automatically adjust based on variables such as quantity, gender, or other contextual inputs.

This system is essential in software localization, where content like notifications, user messages, and UI text often depends on dynamic data. It allows translators to focus on conveying the intended meaning without restructuring sentences manually for every case or language.

For example, in English, the sentence “You have 1 new message” changes to “You have 5 new messages” depending on the number. In other languages, the change might involve gender-specific words, different sentence structures, or alternate verb conjugations.

ICU Message Format enables this by using placeholders and conditional logic, ensuring that messages are grammatically correct and natural-sounding in all supported languages.

🧩 Highlights of ICU Message Format: #️⃣

• Handles pluralization, gender variations, and context-based message structures
• Uses placeholders to insert dynamic values such as numbers, names, and dates
• Supports nested messages and conditional formatting for advanced use cases
• Integrates with localization platforms like Localazy, Phrase, and Transifex
• Keeps translations consistent and reusable across multiple contexts
• Reduces the need for multiple translation strings per language
• Improves translation speed by minimizing structural rework

🛠️ Example: #️⃣

"You have {NUM_MESSAGES, plural, one {# new message} other {# new messages}}."