clutches,Sifter floats from gear to gear and when letting out the clutch there is no response.

Driving in 4th gear coming up to red light put it in 3rd gave it gas and I could feel no response from the car. Coasted to the side of the road to see the problem. Sifter goes from gear to gear but it doesn't feel like its able to fall in gear. can have clutch out and shift through the gears with no response. A friend mentioned maybe the linkage is jammed up so I need some input please.

My car has 180000 miles.
My car has a manual transmission.