此方法根據 ICU 標準執行 Level 1 和 Level 2 正規化。請參閱 http://userguide.icu-project.org/locale#TOC-Canonicalization.
echo \Locale::canonicalize ( 'en-US.utf8' );
// "en_U"
echo \Locale::canonicalize ( 'FR-fr@EURO' );
// "fr_FR@currency=EUR"
echo \Locale::canonicalize ( '' );
// "en_US_POSIX"