I know I've successfully fooled you into thinking I'm not a tourist, but um, yeah, I don't speak your language. And the more butchered your accent is, the better it'll help your case.
French: Je ne parle pas français.
Spanish: No entiendo español.
Arabic: لا اتكلم العربية.
Mandarin: 我不会讲中文 [Pinyin: Wŏ bù huì jiăng zhōng wén.]
English: Yeah, you do.