As you type, the iPhoto spell checker underlines and marks questionable words in red. You can correct these words or leave them as they are.
You can also check the spelling of selected text, and see recommendations from the spell checker.
To check the spelling of a specific section of text:
Click the text block you want to check, press the Control key and click the text again, and then choose “Spelling and Grammar” > “Show Spelling and Grammar” from the shortcut menu.
For each questioned word, choose an option:
To accept a suggested spelling, select it, and then click Change.
To correct the spelling yourself, type the new spelling in the top field, and then click Change.
To keep the current spelling, click Ignore.
To keep the current spelling and add it to your dictionary (so that the spell checker doesn’t question it), click Learn.
To move from one questioned word to another, click Find Next.
To have iPhoto read text aloud:
If you want, you can have iPhoto read your text aloud, so that you can hear if it stumbles over a typo or awkward language.
To turn off automatic spell checking:
Choose Edit > Spelling > Check Spelling While Typing (so that there’s no checkmark next to the last item).