Localisation means adapting the app to a language and region, including how dates, numbers and currencies are written. Translation is only one part.
Build it in from the start
- No text in the code. All strings live in language files managed by the platform’s system.
- Plurals and grammar. Many languages have more plural forms than English, and some need different word forms depending on context. Do not build sentences by joining pieces.
- Formats. Dates, times, numbers and currencies should come from the system, which knows local conventions.
- Layout. German and some other languages produce longer text; the interface must not break.
- Right-to-left languages need mirrored layouts if you plan to support them.
- Images with text should be avoided or localised too.
People, not only tools
Machine translation is a useful draft, but a native speaker should review it. A wrong or awkward phrase in a button or a legal text can cost trust or cause real misunderstanding.
Do not forget the store
Listings, screenshots and keywords can be localised too, which helps people in that country find and trust the app. Privacy policies and support information should exist in the languages you support.
Choose languages by where your users actually are, not by a wish to be everywhere. Kinship is available in English, Czech and Ukrainian, and each language was a deliberate addition, not a checkbox.