Q: when i answer my iphone 4 it automatically goes into speaker mode,how do i get this to stop?

I think as a starting point I would try a restart/reset of your device. 

http://support.apple.com/kb/HT1430

Hi I had this problem too.  From looking on this help page I used this method: Go to Settings - General - Accessibility - Scroll right down to Physical & Motor - Select 'Incoming Calls' - Select 'Default' For me that solved the problem.  Hope it works for you

have a iPhone 6 and it was doing the same thing. Went to Settings-General-Accessibility_Call Audio Routing and found that somehow it had been changed to Speaker. Checked Automatic and it went back to normal. sandrafrommilton keynes......you're the bomb !!!!!