Comment 20 for bug 315740

Before the changes to the Compose files can be pushed, we need to
decide on what character to use for the apostrophe in the cʼh strings.

I spent some time before the holiday researching that.

The fdo bug reports and related posts in the list archives use U+2019
RIGHT SINGLE QUOTATION MARK.

Every Breton site I found (by way of google) uses U+0027 APOSTROPHE
(aka the ASCII apostrophe).

But neither of those characters are letters.

The character U+02BC MODIFIER LETTER APOSTROPHE probably is the most
accurate choice, from the point of view of the UCS and Unicode. It
is a letter, not punctuation, so word break algorithms and the like
should Do The Right Thing. Google and the like map all of U+0027,
U+02BC and U+2019 together when comparing, so web interaction should
not suffer.

On the other hand, only the libré fonts tend to have glyph support for
U+02BC (generally as a homoglyph to U+2019), the commercial fonts seem
to ignore it.

Thoughts?