Why does my TextEdit not like ff & fi

[blackxacto]

High Sierra TextEdit app: why does TextEdit always warn me about words that have the letters ff or fi? The words are spelled correctly, so why am I getting a warning to check them? Is there a way to get TextEdit to accept the letters ff & fi?

 

[jakeOSX]

High Sierra TextEdit app: why does TextEdit always warn me about words that have the letters ff or fi? The words are spelled correctly, so why am I getting a warning to check them? Is there a way to get TextEdit to accept the letters ff & fi?

to guess, both ff and fi are common ligatures, so it may have something to do with the font family you are using.

 

[kohlson]

why am I getting a warning to check them

You may want to investigate Text Edit Preferences - Text Replacement (uncheck)

and/or

Edit - Substitutions.

As blackxacto said, these characters are likely getting replaced with a ligature, which is not really what TextEdit is about.