The speech was a dud. His source material is a six year old book that has been basically disavowed by the author, picked apart by the media as being false, and generally thought of as having less gravitas than a comic book.
When he tried to quote Lincoln he sounded like a child trying to pronounce words that he just learned.
It was a pack of lies, entertaining to listen to from those that are actually politically aware from the standpoint of the falsities, and is easily dismissed.
***
Moving beyond the carcass of the speech though, one does find some intrigue in why it was given. Either this small fraction of a man who makes fun of the handicapped really thought this book was a legitimate reference work or he gave this cartoonish speech as a matter of satisfying some requirement of getting funding from the RNC or some other fat cat.
I'm betting the latter. Surely not even Drumpf can't be this removed from professional politics.