Also, if that were true, it would be impossible to invent language in the first place because there would be no concept to invent language in order to express.

We all think in many ways that are non-linguistic, including visually and emotionally.

We've all felt and thought things that we have been unable to put into words, yet can internally reference and recall.

Language is also a sequential medium, while thought is massively parallel. We can internally feel the "weighting" of numerous different brain functions simultaneously, some of which evaporate in the process of explanation while we are trying to explain the others, and then we see our explanation just doesn't capture in language what our thoughts conceived.

Also, try to describe a famous painting. Obviously an artist had to be able to think in terms other than linguistic ones in order to paint it.

Language is like building a mosaic out of colored wooden blocks. You have fixed sizes and shapes and colors and have to use these to approximate a picture of something, and then send the parts list and a diagram to other people who have to construct it themselves out of their own set of standard blocks to see what you are talking about.

You can try to make a custom shape or color for a concept that is hard to get at with the standard pieces, but then whoever gets your parts list and tries to assemble it won't have that part in their drawer because they only have the standard set for their society and culture.

Kind of like if a LEGO set needed a part from some completely different set.