One of the main drawbacks to Siri is that some things often get lost in translation. If Siri can't pronounce certain words correctly, for example, street names, it's going to be difficult to use it to order yourself an Uber. You'll also have trouble finding contact information via Siri if the pronunciation is incorrect. Basically, it's just better if Siri knows what's up.
When Siri pronounces a name incorrectly, let's use 'Bob' for this example, say "That's not how you pronounce Bob." Siri will then respond with "Okay, how do you pronounce it?" Speak the name and Siri will provide you with a list of pronunciation options, along with a little thank you message. Choose the correct one and Siri will always know how to say it! It takes a bit of work, but Siri always gets there in the end.