Fill in the blank with the most appropriate word.

You have memorised your speech, ______ you?

haven’t

The correct word to fill in the blank is haven't.

• Hasn’t is the negative form of the verb "have" used with the third person singular subject "you." It is not the most appropriate word to use in this context, as it is not used to ask a question.
• Couldn’t is the past tense of the verb "could" used to express inability. It is not the most appropriate word to use in this context, as it does not refer to whether or not the person has memorized their speech.
• Didn’t is the past tense of the verb "do" used to express negation. It is the most appropriate word to use in this context, as it refers to whether or not the person has memorized their speech.
• Have is the present tense of the verb "have" used to express possession or to indicate that something has been done. It is not the most appropriate word to use in this context, as it does not refer to whether or not the person has memorized their speech.