Language is not essential for the cognitive processes that underlie thought

As always, barely anyone reads the actual claims in the article and we're left with people opining on the title.

The claims here are exceptionally limited. You don't need spoken language to do well on cognitive tests, but that has never been a subject of debate. Obviously the deaf get on fine without spoken language. People suffering from aphasia, but still capable of communication via other mechanisms, still do well on cognitive tests. Brain scans show you can do sudoku without increasing bloodflow to language regions.

This kind of stuff has never really been in debate. You can teach plenty of animals to do fine on all sorts of cognitive tasks. There's never been a claim that language holds dominion over all forms of cognition in totality.

But if you want to discuss the themes present in Proust, you're going to be hard pressed to do so without something resembling language. This is self-evident. You cannot ask questions or give answers for subjects you lack the facilities to describe.

tl;dr: Language's purpose is thought, not all thoughts require language

This. Also the question is what the possible complexity of the question is that you want to convey. As long as it is rather simple it might seem realistic to argue that there is no language involved (i would argue this is wrong). But as soon as the problems get more complex, the system you need to use to communicate this question becomes more and more undeniably a form of language (i think about complexity here as things like self-referentiality which need sufficiently complex formal systems to be expressed – think what gödel is about). So this part seems more complicated than it is understood. The same goes for the brain-imaging argument. As a philosopher I have unfortunately seen even accomplished scientists in this field follow a surprisingly naive empiricist approach a lot of times – which seems to me to be the case here also.