Does anyone know?

As I was reading I came across several things that didn't make sense to me today - maybe some of you can help me to understand...

1. When Joseph's brothers were in Egypt they were talking to each other and it says "They did not realize that Joseph could understand them, since he was using an interpreter." - At this point did they all speak different languages? Because he'd been talking to them before just fine. Also, I am still finding it hard to believe they didn't recognize their own brother!!!

2. Who exactly is the daughter of Herodias and why did she even want the head of John the Baptist? I feel like I should know this but I don't...And why did she take it to her mother? Not something I'd be proud to show off.

If anyone has any insight, please let me know:-)
~ Sarah