International Components for Unicode

International Components for Unicode, commonly abbreviated ICU, is a set of libraries providing Unicode text processing and software internationalization services. Its C/C++ and Java implementations support tasks such as character encoding conversion, Unicode normalization, text-boundary analysis, language-sensitive sorting and formatting. A software locale selects conventions for a language or region; it does not change the abstract numerical value being formatted.^[ref]

For a text example, a visually accented letter can be represented by the single code point U+00E9 or by U+0065 U+0301, a base letter followed by a combining accent. Those sequences differ as raw code-point arrays. A Unicode normalization service can bring these canonically equivalent sequences into the same normalization form before a comparison. This is distinct from translating a word or deciding a language-specific sort order.^[ref]

Such services make a useful division of labor: the application supplies meaning and policy, while a library implements detailed text and formatting rules. Storing text as UTF-8 alone does not implement software internationalization; the program must still handle boundaries, comparisons, numbers, dates and displayed messages appropriately.^[ref]