Hello and Welcome to Android Forums!
The Grand is going on three years old and by today's standards, lower resources. For example, 1GB ram can get rather full, especially after years of use.
While I'm not sure about the silence, the sluggishness and the multiple swipes are indicative of a device that is over-taxing available resources. If you have applied any system updates and never reset the phone, there can be things lurking around that can slow performance as well. A couple of things you can try ... first if you know how, boot into recovery and clear the system cache. I don't really recommend cache cleaning apps. Some of them are ineffective and others are downright dangerous.
Really, I think the best thing for you would be a factory reset. This will clear out your apps and user data and set everything back to default for the CURRENT version of android you are running. So, if you got the Grand with 4.1 and you've since upgraded to 4.2, a factory reset will keep you on 4.2.
Before you do anything please please PLEASE backup everything important to you. There is no "undo" in Android and once files are gone ... well, let's not even think about that *shudder*.