Can rational thought exist without language?

There are many kinds of language, including chemical formulas, music and mathematics. All of these are essential to their specialist types of rational thought.

But there are practical ways of rational thought which don't require language. For instance, by observing that water flows downhill, flows into channels, and can be contained in bowl-like shapes, we could work out and create plumbing without the need for any kind of language.

There is also a definition of rational specific to psychology. Emotional intelligence requires a commitment to accepting reality as it is and empathy for other sentient beings. Neither of these requires language - but they are the foundation for ethical, sane, and hence a functional life.

That said, even if language is not essential to [i]all[/i] kinds of reasoning, when used well it is a superb aid.

You get a first for bizarre question 🤔

If we're talking just about spoken language, then rational thought can proceed just fine without it. By a more inclusive definition of "language" which includes the form of internal thought, I think the answer would be no.

No it takes words to think a thought. Especially abstract ideas.

Well animals can figure things out without language so yes.

Yes but it's unlikely to be adequately expressed to many

Helen Keller was very wise.