Why do the Hebrew Alphabetic Presentation Forms Exist

[Richard Wordingham]

On Thu, 4 Jun 2020 16:30:20 -0400
"Mark E. Shoulson via Unicode" <unicode at unicode.org> wrote:

> On 6/4/20 3:31 AM, Marius Spix via Unicode wrote:

> > We also have special glyph variants of the same character for
> > special purposes, like an open tail g for IPA (ɡ, U+0261⟩ or an
> > alternative phi for math (ϕ, U+03D5),  but these are completely
> > optional and have no different meaning from the closed tail g and
> > the curled phi. As far as I know linguists and mathematicians
> > accept both glyph variants mutually interchangeable. I guess, they
> > are only in Unicode for historic reasons.  

> Not so!  Contrariwise, in fact, at least for the IPA ɡ.  The reason
> it is encoded is because IPA stipulates that the symbol for the
> voiced velar stop be written ɡ with an open loop, and it is incorrect
> to write it with a binocular g.

The IPA threw the towel in on that one, and now allow either.

>  Linguists do not consider these to
> be mutually interchangeable.  Same with the IPA ɑ, which is wrong if
> written two-storey.

That's different.  [a] and [ɑ] are two different sounds.  Of course, it
all gets horribly confused when type faces for children's books use
single storey 'a' and open loop 'g'.

>  I'm not sure about mathematics usage, but I
> think that there may be situations in math wherein φ and ϕ were used
> with distinct meanings (and not just by an isolated author.)

I suspect that's the difference between curly phi and straight phi.  I
must say though that I need a soft stroked phi that drops the part
above the circle when one applies a superscript.  I'm British and I
find the fluxion notation useful.  (And no, differentiation was
introduced to me with the 'd' notation.)

Richard.