Orthographic normalisation

A module to do orthographic normalisation on input streams would be nice. Some are more complicated than others.

Romanian

Romanian has two characters that should be written with commas but are often (probably over 90% of text "in the wild") written with cedillas. An orthographic normalisation module would convert the legacy version into the new version.

• ţ → ț
• ş → ș

Serbo-Croatian

There are a couple of special characters in Serbo-Croatian which can be written with two characters or one character, a decision must be made which version to use in the dictionaries, and then forms not like this need to be converted:

• dž ←→ dž
• lj ←→ lj
• nj ←→ nj

Afrikaans

The indefinite article in Afrikaans is "'n". This can be written a number of different ways:

• 'n U+0027 U+006E
• ‘n U+2018 U+006E
• ʼn U+0149
• ’n U+2019 U+006E

This ideally needs to be merged into one form.

Lingala

See also: Unicode issues

When a character has an accent, sometimes there is more than one way of representing it, using either pre-combined (sometimes referred to as pre-composed) or combining characters. These look different when encoded in UTF-8, but the same to the user.

UTF-8 0xC3 0xA0 vs. 0x61 0xCC 0x81
      á         vs.      á 
      U+00E1    vs. U+0061 U+0301

The best thing to do is probably standardise on one variant for analysis/generation, and then normalise all input coming into the analyser using a transliterator or something similar.