How do I insert English letters with pronunciation symbols over the letters (like a Dictionary does)?

Click Insert > Symbol. In the dialog box that appears:

• At the top left, set the Font dropdown to "(normal text)" unless you want a specific font.
• At the bottom right, make sure the "from" dropdown is set to "Unicode (hex)".
• At the top right, set the Subset dropdown to "Combining Diacritical Marks".

In the center of the dialog, starting at the highlighted square, you'll find a series of the symbols you want -- accents, a macron, a breve, and so on. Each of these "combining" characters, when inserted, will combine with the character to its left.

For each character, you can use the combination shown at the bottom of the dialog as the shortcut key; for example, type the letter o followed immediately by the number 0304 and then press Alt+X to create a letter o with a macron (the "long vowel" mark) over it. However, if you expect to use these marks often, click the Shortcut Key button and assign a shortcut that's easier to remember and use such as Ctrl+_.

One other note: While the Symbol dialog is open, you can click in the document and continue to edit, coming back to the dialog when needed. You don't have to keep closing and reopening the dialog to insert multiple symbols.

While you can use the Combining Diacritical Marks that Jay refers to, it's much simpler to use the characters that already contain the macron and breve. You can find these in the Latin Extended-A character subset, as follows:

Latin capital letter A with macron: 0100

Latin small letter a with macron: 0101

Latin capital letter E with macron: 0112

Latin small letter e with macron: 0113

Latin capital letter I with macron: 012A

Latin small letter i with macron: 012B

Latin capital letter O with macron: 014C

Latin small letter o with macron: 014D

Latin capital letter U with macron: 016A

Latin small letter u with macron: 016B

In that same character subset you'll find many other useful characters. If you need the schwah, the capital is at 018F, the lowercase at 0259.

The complete list of Latin Extended-A characters is at https://en.wikipedia.org/wiki/List_of_Unicode_characters#Latin_Extended-A (and there are lots of other Unicode characters in other tables in that article). You can find the character you want in the second column (headed "Glyph") and get the number from the first column (headed "Code") -- just ignore the "U+" part and take the four-digit hexadecimal number. When you type those four digits in a document and press Alt+X, Word converts the number to the corresponding character.

The Insert > Symbol > More Symbols dialog shows the same information for the chosen character at the bottom of the dialog (I've put a red box around it here):

Or you can just click on the character to select it and then click the Insert button. Or, as suggested elsewhere in this thread, you can click the Shortcut Key button and assign a shortcut for the character.

Thank you both, Jay & Suzanne.

I, too, regularly use the Alt+ extended characters, and I just found the additional ones beyond Alt+ 0255.

In addition to the acute & grave & circumflex & umlaut & tilde & cedilla accents in characters Alt+ 0192-0221 (from the Numeric Keypad only) & Alt+ 0224-0255 (with a couple exceptions), there are Alt+ 0256-0390 (likely more, but 390 is where I stopped, as it gave the Long- & Short- pronunciation symbols for all the five English vowels, in both small case and capitals.

If there is a non-macro keyboard shortcut, perhaps similar to the two-key combination for an accented letter "é" by hitting Ctrl+' then the "e" key, small or capital, I'd be interested.

For instance, is there a (non-macro) way to hit, say, Ctrl+ ")" then the small-case "a" for a short-"a"?

Part of my goal includes not having to change fonts.  The "schwa[h]", you say, is at Alt+0259, but I get the short-a character at 0259 in Goudy Old Style, and I do not see the schwa in that font anywhere from 0256-0390.  (0282 is at the end of the "e's", but only shows up as a box.

One other specific character or marking would be to add the aspiration mark ‘ (the reverse single curly quote mark, Alt+ 0145) above the Symbol font or other Greek font(s) where (usually) a vowel starts a word.  Ideas on that one, too, please?!  Thanks for y'all's help.

I see I got carried away with the macrons (macra?) and didn't note the breves (brevia?), but of course you'll have discovered them immediately following the macrons.

If you can use a single opening quote for the rough breathing (dasia), then you can insert it via Ctrl+', '. But if you need the mark above a vowel, then you can use U0314, Combining Reversed Comma Above. Alternatively, the Greek Extended character subset includes vowels with all the required accents, breathings, and combinations. You could assign keyboard shortcuts to them.

As for the vowels with macron and breve, it is easy to assign custom keyboard shortcuts for them. In the Symbol dialog, click Shortcut Key, and then type in your desired shortcut and click Assign. I would suggest the following:

Ctrl+- (hyphen), a for lowercase a with macron (Word will show this a Ctrl+-, A)

Crtl+-, A for capital a with macron (Word will show this as Ctrl+-, Shift+A)

Ctrl+(, a for lowercase a with breve

Ctrl+(, A for capital a with breve

And so on for the rest. Unfortunately, Word won't accept Ctrl+), which would be more intuitive.