"...Unicode's normalization is the concept of character composition and
decomposition.
Character composition is the process of combining simpler characters into
fewer precomposed characters, such as the n character and the combining ~
character into the single n+~ character. Decomposition is the opposite
process, breaking precomposed characters back into their component
pieces...
...Normalization is important when comparing text strings for searching
and sorting (collation)..." [Wikipedia]
Performs the 4 normalizations:
NFD: Canonical Decomposition NFC:  Canonical Decomposition, followed by
Canonical Composition NFKD: Compatibility Decomposition NFKC: Compatibility
Decomposition, followed by Canonical Composition Complies with the official
Unicode.org regression test.
Uses UTF8 binary strings natively but can normalize a string in any UTF
format.
Fully tested with phpUnit. Code coverage test close to 100%.

• Vitaly Lipatov

• pear-I18N_UnicodeNormalizer