Pseudolocalization

Pseudolocalization is a software testing technique used to simulate translation of user-visible text without performing actual linguistic translation. Its primary purpose is to expose internationalization (i18n) and localization (L10n) issues early in the development cycle, such as UI layout problems, encoding errors, and assumptions about string length or plurality.

In practice, pseudolocalization replaces user-facing strings with artificially altered equivalents. Common methods include expanding string length to mimic translations that are longer than the source text, substituting characters with accented or non-Latin counterparts, and inserting characters from different scripts or bidirectional markers to simulate right-to-left languages. Pseudo strings may be visibly marked or wrapped to distinguish them from real translations, and placeholders, formatting tokens, and embedded variables are preserved to test string assembly and runtime formatting.

Pseudolocalization is used to reveal a range of issues, including text overflow, truncation, or misalignment in user interfaces, reliance on hard-coded strings, and flaws in string concatenation or pluralization logic. It also helps detect encoding problems, font coverage, and the handling of locale-specific data such as dates, numbers, and measurements. This technique is typically integrated into development and quality assurance workflows and can be toggled via configuration or build options to run alongside normal testing.

While useful for identifying many i18n and L10n concerns, pseudolocalization does not replace real translations or cultural adaptation. It is most effective when used in combination with actual localization processes and culturally aware testing.