The kind of amnesia portrayed in films like 50 First Dates is called anterograde amnesia, where the patient is unable to form new memories after the date of the event that caused the condition.

Rebracketing is the historical linguistic process by which words (and typically their articles) are broken apart and recombined while still retaining their meaning; it is by this mechanism that, in English, “a nadder” became “an adder” and “a napron” became “an apron”.