You are more likely to face a convicted felon high on meth than a "trained" knife fighter. In that case you have a few things going for you.
First, most edged weapons the goblins carry are either good at slashing or stabbing and seldom both. This coupled with what I have found to be primitive vs trained motion will have them attack violently and repeatedly in one of two basis ways.
Angle #1 which is a slash traveling high right to low left for a right handed attacker. Will look like a round house punch.
Angle #1 is a stab at any angle. It will most often be overhand but in some cases underhand.
Once they make contact it is likely that task fixation will set in and they will continue the same angles of attack. Here his something I wrote a while ago on dealing with edged weapons.

