"Focal": means limited to a specific area.

"differentiation": In cancer, refers to how mature (developed) the cancer cells are in a tumor. Differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated or poorly differentiated tumor cells, which lack the structure and function of normal cells and grow uncontrollably.

Here is a resource for cancer terms: http://www.cancer.gov/dictionary/

Tongue cancers can be pretty aggressive, I would be suspicious if they didn't recommend radiation -even in a stage II.

I found it essential to have a good note taker throughout all of this.