Special text is very "special".  It's used to create a one-off instance of a
text item which is based on another type of text item.

Suppose you want a rehearsal mark which says start instead of "A". You can't
get this by using a regular rehearsal mark because these are fully
automated. Instead, you would do the following:

1. Select the note that the rehearsal mark will go above.
2. Choose Create > Text > Special > Rehearsal mark.
3. When the edit window opens, type in "Start".

The word start will now appear above the system in bar 1 and will be bolded
and surrounded by a box. It will also be a fully functional rehearsal mark
with all the properties of the other marks.

You don't need to use special text items except in "special" circumstances.

Viz. D.C., D.S., etc, you need Create > Text > System text > Repeat.

If you really have a head for shortcuts, its Alt+C then X then H then R.

The first four items are characters in the opus font and so JAWS will speak
the ASCII character instead of the actual character. The actual characters
are segno, large segno, coda, and large coda.