Stacking Diacritics
Until now, one of the main limitations with using diacritics with computers has been difficulty in placing more than one diacritic above or below a base character. For the diacritics to be properly positioned relative to each other and the base character, solutions involved having a separate glyph in the font for the combined diacritcs, or a separate glyph for the diacritics with the base character. These solutions can work for single languages, using few diacritics. No such solution can work well with multiple languages using large numbers of diacritics in combinations, like Yukon languages.
It is now possible with both Macintosh and Windows to treat each diacritic like a separate character. Each has a single shape (glyph) encoded in the font, and there is special programming to ensure that each displays in the correct position.
Using the YNLC package, it is easy to not only get single marks above 
and below
but also combinations above
and below
. Any two superscript or subscript diacritics may, in theory, be placed in any order above
or below 
a base character. Actually, both Mac and Windows appear to allow the use of more than two accents above and below a letter. The limitation to this may be the line spacing in the font, which would cut off the display of accents as they get farther from the base. For practical purposes, two diacritics above and below are probably adequate for almost all specialized uses of the roman alphabet.
The ability to add new combinations when needed is a strength of this approach. It allows a single font and keyboard package to be used for a great many languages. It also permits language workers to employ new combinations as needed, rather than requiring purchase or development of another font.
