I can fully relate to this.
I'm half chinese with my family being from toisan so we speak both cantonese and toisanese, but as is my case with my grasp of the language I sometimes unknowingly speak a blend of the two. Toisanese people should be able to understand cantonese ( they are very closely related) To address the comment above, in my opinion Toisanese is much more closely related to Cantonese, some most words are very close to the same with only a slight difference in pronounciation, as well as some words being the same. Also as you are probably aware the writing and therefore the reading is the same.
To learn, this to me would seem quite hard unless you meet someone who has the grasp of the two languages and english. It is already quite hard to find proficient online help for cantonese (living in canada).