The severity of the corner is represented with these notes in this order.
Flat
Easy
Fast
Medium
K
90
Hairpin
They in turn have additions like tightens, opens, long etc. The
The pacenotes are called out a good distance before the corner (with an adjustable slider) often relating to one or two corners in front of you.
It works something like this. "Start" 100 "pause" K Right Don't Cut 60 "pause" Flat Left into Fast Right Long 80 "pause" Medium Right Tightens into Fast Left Narrows 150 "pause" Keep Left over Crest 60 "pause" Easy Left Cut Keep Right over Jump 100 "pause", and so on.
There are ofcourse loads of other notes in the game representing water, caution, bumps etc. But you get the picture.