Positive and negative expression seems like an elementary component of language but it is actually an enormously difficult concept to convey mechanically and semantically. No two languages express the ideas of yes and no isomorphically. The yes/no polarity in English is actually a degradation of a previous, more complex system for affirmation and negation which made use of 4 different expressions: yae, nay, yes, and no. If a question were framed in the affirmative, like “Dost thou wish to visit the country on this fair morn?” one would answer yea to consent or nay to decline. If, on the other hand, the question were posed in the negative: “Wouldst thou not look kindly upon a pleasant stroll over the country lane?” the respondent would reply yes or no. It was apparently confusing distinction to maintain even back then since we see writers in Renaissance England correcting each other on usage and ultimately discarding yea and nay altogether in by the 18th century. Why speakers preferred the answer to the negative question over the affirmative is not clear. One assumes assent questions must have taken the frame of the negative more often when the shift occurred.
Other Germanic tongues made use of similar systems and then also underwent semantic contraction to binary expressions of positive and negative. Most often they would have two different words for yes and then a single no term. Languages that pre-date the barbarian invasion of Europe such as Finnish, Irish and Welsh have no words for yes and no response. In these languages, the respondent either assents by repeating the sentence or declines by negating the sentence. So, if asked, “Do you want to play ball?” you would respond by saying either “I do want to play ball” or “I do not want to play ball”. This is what is called “echo response.” It is actually the most common way of communicating positive and negative response throughout the world. All of the East Asian languages apparently employ echo response to convey agreement. To my mind, echo response is less ambiguous and more expressive than single word yes/no reply. A respondent can communicate a great deal of feeling and attitude in the way he or she repeats the question’s phrasing. I find it more logical as well. What you are essentially doing when you say yes is consenting to the view of the world that the questioner is putting forward. Repeating the proposition creates an accord. It is performative and more immediate. When you respond with the word yes, you are actually labeling the question with a positive identifier and thus placing an intermediary sign between you and the proposition to complete the concurrence.
None of the ancient languages have a word for yes. Greek, Latin, Hebrew employ either echo response or intensifying adverbs to indicate consensus. In place of the positive expression, the Roman would have simply said sic: “It is thus.” Meaning, what you say is true, and I see it that way too. In the classical mind, affirmation was more about conferring truth value onto a proposition rather than displaying agreement.