what is the word to say a disease who forget all his past....but?

Question

in some moives, when he/she start to be conscious, he/she
forget past and still can speak..that means
he/she sti; remember the language and words.. how come?

Answer 1

Do you mean amnesia? If so I don't know why language skills are not degraded.

Answer 2

it's called amnesia and the reason they can remeber the language and words is because different parts of the brain controll different memories or actions. The part of the brain that controls memory must have been damage somehow. it can also be phsycological , maybe that person is blocking it out unconsciously.