The trackpoint (red thingie on the keyboard to control the mouse cursor) may be too sensitive for you; the mouse settings in the Cinnamon desktop environment (and possibly other DEs as well) don't affect the trackpoint much.
Here is what you can do, based on these AskUbuntu answers. For present-day Linux versions (2019), try this ($ indicates commands that you enter):
$ xinput | grep -i trackpoint TPPS/2 Elan TrackPoint id=12
Then, use the above string identifier:
$ xinput --list-props 'TPPS/2 Elan TrackPoint' ... libinput Accel Speed (300): 0.000000 libinput Accel Speed Default (301): 0.000000 ...
Experiment with the Speed setting; negative values allowed. For example,
$ xinput --set-prop 'TPPS/2 Elan TrackPoint' 'libinput Accel Speed' -0.25
(Instead of the string 'TPPS/2 Elan TrackPoint', you can use the id number '12', but this value may vary if you have an external keyboard or mouse plugged in at login time.)