Use VoiceOver to complete partial words on Mac
When you start typing a word, you can display a list of suggestions for completing the word.
As you type, enter as many characters as you know, then press F5 (do not use the VoiceOver modifier). You may need to press Fn-F5.
Press the Down Arrow key until you hear a word that sounds correct.
To hear how the word is spelled, press VO-W-W. To hear the word spelled phonetically, press VO-W-W-W.
When you hear the word you want to use, press the Space bar.
The word you selected replaces the text you typed.