Why can't I use forgot in this sentence?
I'll have to go back, I've forgotten my wallet at home.
Why can't I use forgot in this sentence?
I'll have to go back, I've forgotten my wallet at home.
to not bring something with you because you did not remember it: I forgot my keys.
non standard: I forgot (left) my wallet at home. Cambridge Dictionary
The non-standard forget for leave is used in speech even though the dictionary says it is non standard. It is colloquial.
So, forgotten my keys at home means have left my keys at home.
BASIC DIFFERENCE have forgot/forgotten: present perfect signals the past but not when something occurred. forgot: simple past tense implies an event which is now finished.