I have lived in the USA for 23 years. This June my 78 year old mother who does not speak any english will be flying from Frankfurt to Chicago to visit me.
Which Airlines traveling the Frankfurt ( Or Munich ) to Chicago route ( non stop) have flight attendants that speak German and would be able to assist her ?
I am wondering about Airlines other than Lufthansa obviously .

Most international flights have attendants that speak a few different languages, regardless of where you're coming from.
I flew to Frankfurt with Lufthansa a few years back and they all spoke German. But, if you want to use another company for price reasons and are worried you can probably call and find out.