Yes and No are Unnecessary.

Not all languages have words for "yes," and no," or if they have them, they are not used much. Latin was one. Mandarin is another. The rural Irish, even when speaking English tend to avoid them, because Gaelic does not use them and they seem to have just gotten into the habit.  Whether it technically has those words I don't know. Consider this interview with a woman in New Zealand. The interviewer is setting up the questions intentionally, and I think the woman is in on it, particularly from her last two answers, yet I feel confident these are essentially natural answers for her.

Your name is Sharon?

It is.

And you're from Ireland?

I am.

You have been in New Zealand for ten years.

I have.

And you would like to be a psychologist.

I would.

And your favorite food - is ice cream.

It is.

And today is a beautiful day.

It is.

And you have never been to Iceland.

Never.

Can you tell me a three-letter word that means affirmative?

Aye.

I notice the Irish never say "yes" or "no."

To be sure.

You will notice that the most common version is to use a word the other speaker used, especially a form of the verb, either in positive or negative:  Have, do, is, never. It is not that strange to English speakers as we would think at first, even though we use "yes" and "no" a lot.  The Irish woman gives responses that we might also use to go through life without anyone ever noticing an idiosyncrasy.  "Is that your car?" It sure is! "Do you ski?" Not anymore. Are you going to Florida for the winter? Absolutely. We use these other forms when we want to give our answer a special emphasis, but we do have midrange forms as well. "Can I borrow your sledgehammer?" Sure. Okay. Uh-huh. We could get by without yes and no if we needed to.