I think transforming “it’s possible to think without language” into “language is not a tool for thought” is an overreach. Definitely a lot of our internal voice is post-thought, but crystalizing those thoughts into words can provide footholds for further thought. Some would argue it’s not possible to think through a complex issue without writing:

• https://paulgraham.com/words.html
• https://www.youtube.com/watch?v=vtIzMaLkCaM&t=312s