How do I get my iPhone 4s to make sounds when I get a new text or email?

[iMore Question]

I used to get a tweet whenever I received a new text. For some reason, I no longer hear any sound. And I have the same issue with new emails. How do I get the sounds back? I've tried checking my settings but I can't figure out what's wrong. Any help would be greatly appreciated!

 

[kch50428]

Settings>> Sounds>> select for events... adjust volume...