Simply Curious

What are the first words you learn when you study a new language?  Yes, no, thank you, hello, sir, ma'am, numbers and colors, right?  And you're EXCITED to be able to use them.  I know how to say something without having to think hard! 

So here's my rant.  In movies and on TV, whenever you encounter a 'foreigner,'  he speaks perfect English, except for those basic words!  "Si, Senor, the ruffians absconded with the assets.  Will you pursue them?  Gracias!"  Characters pretending to be foreigners can get away with this, too. 

 I'm certainly not going to get into the old Native American movie jargon, where they appear to be unable to produce proper English grammar, in spite of hearing it regularly.

 I realize it's just a simple, quick method of establishing a national identity, but . . . but . . . it shouldn't work!