Language is a major component of thought. Every programmer knows the unreasonable effectiveness of rubber duck debugging whereby one can solve logical problems

Language is a major component of thought. Every programmer knows the unreasonable effectiveness of rubber duck debugging whereby one can solve logical problems more effectively by talking aloud. If language were merely a tool for communicating thoughts rather than an integral part of thinking, then talking aloud wouldn’t help. But since raising the volume of one’s internal monologue does improve reasoning, this shows that the internal monologue is part of the thinking process - not a passive reflection of thought that is happening “elsewhere”. Yes, of course you can engage in complex thought without language. There is verbal and non-verbal reasoning. A chess player thinks spatially in terms of how the knight moves, not just verbally, though verbal reasoning does help in chess somewhat.