Q: I lost the function for loudspeaker after updating to iOS 7.1.1

Hi Tooth Paste,

Thanks for using Apple Support Communities. Based on what you stated, it sounds like you do not hear sound from the iPhone speakers. I would recommend that you read this article, it may be able to help the issue.

If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support

Cheers