GMAT Sentence Correction (SC) | Re: Lower courts generally accept what the higher courts say is true not o

No,say is not a noun in the original sentence. It's just that it's not necessary for that portion to be what thewhat is really introducing. Perhaps thewhat is actually followed byis , and thethe higher courts say portion is not important. I found a sentence very similar to mine in theWSJ :

But these reforms have been financed by what some economists say is a dangerous rise in government debt issuance...
This
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