So I was reading "Inside the third Reich", and thought I would look up the letter where Speer tells Hélène Jeanty he attended the Himmler speech. (He is pushing the narrative: "I was just an Architect" quite heavily.)
But I only find some seemingly poorly translated quotes in low quality articles: "There is no doubt - I was present as Himmler announced on October 6 1943 that all Jews would be killed". He continued: "Who would believe me that I suppressed this, that it would have been easier to have written all of this in my memoirs?"
What is the full text? (Translated or not.)
Since the letter was sold to a private collector, it is unlikely that it is publicly available. Those publications that do cite it, cite it as "Printed in the Frankfurter Allgemeine Zeitung, 10.3.2007" but I was unable to find the full text online. It might be that they only printed in the, well, print edition, so if you want the full text, you would need to get a physical copy of a FAZ from that day.
While this probably isn't entirely what you're looking for, I was able to find at least what appears to be part of the original letter in question from the auctioneer's website.