Why are my notifications coming from the external speaker?

[AC Question]

I connect speakers through the headphone jack and I want them to play on the phone's speakers, not the external ones.

 

[Rukbat]

You have 2 choices - plug in the speakers and have things play through them, or unplug them and have things play through the internal speakers. Having the external speakers plugged in and having things play through the internal speakers isn't one of your choices. (It's not on any device I know of - TVs, portable radios, phones - anything.)