Student or Learner
I would like to say that I know a lot about Latin America..
but I cannot tell what is the correct form:
Becasue of my regional exepertise on Latin America...
Becaseu of my regional expertise in Latin America
Because of my regional expertise of Latin America
thank you in advance for your help.
1. 'Regional' is a rather strange adjective with which to describe 'expertise' 2. 'Expertise' generally suggests some kind of technical skill (e.g. in teaching, computer-programming or dairy-farming), whereas what you are referring to here sounds more like 'knowledge'.
Hence I would suggest
...my knowledge of the (various) regions of South America.
Depending on what comes next, you could say With my knowledge of....