Well, most languages probably have blind spots. Just listen to native English speakers trying to speak Spanish. The pronunciation is usually a disaster. For example, J in Jose is pronounced as "H" by English speakers, when it's a much thicker sound, I believe written as Kh for the similar sound in Arabic (other languages have that sound too). Ditto for the Gh sound (same as Kh or J for Jose, but with voice applied). By "voice applied" I mean what you do to go from S to Z or from F to V or from Theodore to This.
Which brings the topic to Germans.... who will pronounce Seeodore and Zis because they don't have the Th sounds.
Of course, they have the ü and ö sounds (hah! Compose key on the Kinesis) that don't exist in English.
I won't even touch going from French to English or English to French :-) Peter Sellers takes care of that beautifully in the Pink Panther movies!