unspeak

As a noun takeback

is the act of taking back or reclaiming anything.

As a verb unspeak is

(rare) to retract what one has spoken, to unsay.

As verbs the difference between unspeak and upspeak

is that unspeak is (rare) to retract what one has spoken, to unsay while upspeak is to speak up; advocate.

As a noun upspeak is

a manner of speaking in which the intonation of one's voice rises at the end of a statement, as if expressing uncertainty or asking a question.