Biblical Hebrew has always posed a special challenge to typesetters. First, I am unaware of another language category that is as complex as Biblical Hebrew (perhaps, certain kinds of Arabic, with complicated ligatures, floating accents, and other marks).
Biblical Hebrew features special Hebrew typeface designs conducive to Biblical Hebrew vowel and cantorial marks, accent and stress marks, and symbols for certain grammar rules. So, in effect that's a Hebrew character with up to five floating glyphs positioned carefully above, within, and below the Hebrew character.
If that wasn't complex enough, the design of certain Hebrew characters are very narrow. This makes positioning the various diacritic glyphs very limiting, in order that they all appear together correctly, without bumping into one another.
This is further complicated when the Hebrew character which follows a narrow Hebrew character is either a daled or reish, Hebrew characters which are designed so as to have a vertical bar on the extreme right hand side. This means that the configuration of diacritic glyphs under the narrow Hebrew character, and diacritic glyphs under the specially designed Hebrew character daled or reish which follow it, must be carefully spaced apart, so that the reader does not confuse the pronunciation of the two Hebrew characters.
In the days of metal type, this was rarely accomplished successfully, and in the first generations of computer generated film type, this also could not be perfected. However, with the advent of the advanced features of diacritic placement, OpenType appears to offer the finest placement for Biblical Hebrew ever.
Since Biblical Hebrew is only used in certain texts, namely in the Jewish Bible, very sophisticated look-up tables can be created, directing the font to substitute specially created ligature-like glyphs to avoid bumping glyphs and to enable distinction between diacritic configurations. Futhermore, certain straight-forward grammatical rules can also be defined and included in advanced OpenType Biblical Hebrew fonts, so that Unicode data that did not include special glyphs indicating these grammatical rules could appear and be printed with these special glyphs, with the user having to insert them manually.
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