Greek Unicode duplicated vowels

The Problem

When Greek spelling was reformed in the 1980s, every accent was dropped except the oxia (acute). But experiments in typography at that time (e.g., rendering the acute nearly erect, or in the shape of a triangle), combined with the orthographical reforms, gave the false impression that all previous accents had been discarded in favor of a new and different accent, the tonos. Hence double code points for the vowels with oxiai made their way into fonts and into pre-Unicode encodings that were eventually folded into Unicode (which had to deal with legacy code tables). This legacy is evident in Unicode, which designated two major blocks:

• Greek and Coptic (0370-03FF), which encoded the characters required for modern Greek: the 24-letter alphabet, a couple of numerical symbols, and vowels with tonos and/or diaeresis in addition to Coptic and a few other symbols. (Coptic was later moved to its own block, but the original name Greek and Coptic was retained for backward compatibility)
• Greek Extended (1F00-1FFF), which handled polytonic Greek (for both classical and katherevousa Greek), which handled precomposed vowels with accents, breathing marks, subscript iotas, etc.

The Unicode Consortium soon recognized that the duplicated vowels preserved a false distinction. They therefore established normalizing rules that dictated that the upper code point should always be converted to the lower. But it is common to run into the problem of acute vowels encoded in Greek Extended.

The Characters

For some reason, perhaps because of an oversight, or perhaps because the editors thought that there was some essential difference between tonos and oxia (acute), which there is not. Sixteen characters in the Greek basic set were duplicated in Greek extended:

Unicode	Beta Code	Basic codepoint	extended codepoint
ά	A/	03AC	1F71
έ	E/	03AD	1F73
ή	H/	03AE	1F75
ί	I/	03AF	1F77
ό	O/	03CC	1F79
ύ	U/	03CD	1F7B
ώ	W/	03CE	1F7D
Ά	*/A	0386	1FBB
Έ	*/E	0388	1FC9
Ή	*/H	0389	1FCB
Ί	*/I	038A	1FDB
Ό	*/O	038C	1FF9
Ύ	*/U	038E	1FEB
Ώ	*/W	038F	1FFB
ΐ	I/+	0390	1FD3
ΰ	U/+	03B0	1FE3

There is no semantic difference between, for example, ά and ά (both alpha-oxia), so in most cases you don't need to worry about this. Your Greek Keyboards (Unicode) will make a decision and input one or the other. A search engine should be able to find both from either input (just as they should be able to strip diacritics altogether from a search term, if desired).

The Unicode database dictates a rule for normalization that converts the higher code point to its corresponding lower code point.

Most Greek Fonts (Unicode) will display both versions identically. A notable exception is Adobe Garamond Premiere Pro, which places the accent in the lower code point versions at almost a vertical angle, and the upper code point versions at a slanted, ca. 45-degree angle. This can cause a problem with software that (correctly) normalizes the higher points to the lower ones, producing an inconsistent appearance of accentuation.

Recommendations

There have been problems with this (certain fonts in certain browsers don't get it right, for example). It seems (see discussion from GreekKeys Unicode) that the higher codepoint, in Extended Greek, has been de facto deprecated, by virtue of Unicode normalization rules that turn the higher code point vowels into their lower code point equivalents. By preference all tools and input methods should use the Basic Greek vowel+tonos for these character combinations. Fonts and search tools should continue to support both for the sake of legacy data.