The vowels with macrons ("long marks") and breves ("short marks") are
included in most standard fonts, in the Unicode range "Latin Extended
A." To get to them, click Insert Symbol (the button with the capital
Omega) and set the dropdown at the upper right to Latin Extended A.
You'll find your letters there in alphabetical order. Double-click on
a letter to insert it, or type (on the regular keyboard) its four-
digit Unicode number and then type Alt-X (don't select the code or
anything).
If you're going to use them a lot, assign keyboard shortcuts to them
-- you do that also in Insert Symbol, with the button left of center
at the bottom.
There's one exception. "oo" with macron or breve, as used to be used
in dictionaries for the "food" and "good" vowels, haven't been put
into Unicode. (You can get fonts that include them, but either they've
replaced some standard letter with them, or they're in a part of
Unicode that's used for characters that haven't officially been
included yet.)
You can sort of imitate oo-with-the-marks as follows. Go to the
"Spacing Modifier Letters" part of Unicode, then insert the macron
(02C9) or breve (02D8) between the two o's. Select only the _first_ o
and the macron or breve. Go to Format Font (Ctrl-D), second tab and
set "Spacing" to "Condensed" by (some number that looks right). In 12
pt Times New Roman, 2.1 seems to do it. (You can set Condensed values
by clicking on the down arrow next to the box, but it goes by .1 pt,
so it would take 21 clicks to get to 2.1.)
After you've done this once, you may be able to make it an AutoCorrect
entry With Formatting so you don't have to go through all that every
time. But with different fonts or sizes, you'll probably have to
adjust the Condensation.
