5 Another circumstance by which a stipulation may be avoided is want of correspondence between question and answer, as where a man stipulates from you for payment of ten aurei, and you promise five, or vice versa; or where his question is unconditional, your answer conditional, or vice versa, provided only that in this latter case the difference is express and clear; that is to say, if he stipulates for payment on fulfilment of a condition, or on some determinate future day, and you answer: 'I. promise to pay today,' the contract is void; but if you merely answer: 'I promise,' you are held by this laconic reply to have undertaken payment on the day, or subject to the condition specified; for it is not essential that every word used by the Stipulator should be repeated in the answer of the promise.
"The Institutes of Justinian"
Caesar Flavius Justinian
19 As has been already observed, no one can validly stipulate for performance to a person other than himself, for the purpose of this kind of obligation is to enable persons to acquire for themselves that whereby they are profited, and a Stipulator is not profited if the conveyance is made to a third person.
"The Institutes of Justinian"
Caesar Flavius Justinian
23 If a Stipulator and the promisor mean different things, there is no contractual obligation, but it is just as if no answer had been made to the question; for instance, if one stipulates from you for Stichus, and you think he means Pamphilus, whose name you believed to be Stichus.
"The Institutes of Justinian"
Caesar Flavius Justinian