I disagree. I never had a German client who didn't speak faultless English. My German is pretty good but very provincial (western Austria), we would exchange courtesies in German but when we talked turkey it was always in English.
On the other hand, I did have a client who only spoke Italian . . . how we got that client is a story in itself. Luckily he was a very nice fellow, so I would speak Latin with Italian endings, he would laugh at me, and we managed to work out an understanding. We won his case for him, too, so he was very pleased despite my deficiencies (I had my dad, who is fluent in Florentine Italian thanks to WWII, help me compose a nice report/thank you letter . . . . )