Software localization

Software localization adapts a software product for a particular audience's linguistic, regional and cultural requirements. It includes translation of visible text, but can also involve dates, numbers, currencies, keyboard use, sorting and visual presentation. Software internationalization prepares the product so that these adaptations can be supplied and selected.^[ref]

An original engineering example is an application that displays a transaction amount, a date and a status message. Retain the numerical amount and date as structured values; select display patterns and message resources for the intended software locale. A translated status message can then change independently of the computation that produced the amount.

Suppose the same date value is presented with a month/day/year pattern in one localized interface and a day/month/year pattern in another. Testing only whether the two displayed strings are equal would be the wrong criterion. The relevant check is whether each presentation follows its declared conventions while preserving the represented value. Parsing user input requires the corresponding conventions too.

Resource separation is one enabling design choice: localizable messages and patterns can be changed without replacing the core computation. Localization must still be checked in the running interface, where text length, direction and layout constraints interact. A translated resource file alone does not establish that every control remains readable or that every input is interpreted correctly.^[ref]

This separation makes the work testable. Computational tests can examine stable values and operations, while locale-specific interface tests examine the chosen messages and formats. Both are needed to establish that a localized application still performs the intended task for its audience.