Mostly all true what you said. But Melania is on video saying she wrote the speech MOSTLY herself. My guess is she wrote her biographical content herself, and then embellished by professionals, who probably found previous first lady speeches on google to add.
The campaign said she wrote it with a team of writers, so I think she sat down with them and told them her thoughts, maybe wrote some lines herself, and this was added in. Manafort makes it clear here that Melania herself didn’t write this part.
ALL of what I said is true, LOL.
The point you make in your post is correct also...speech writers will amplify on biographical material and other notes provided by the speaker-to-be.
To add to your observation, the speaker is always free to add or subtract to the speech-writer's end product as he/she sees fit.
However, she appears to have been reading a text provided for her based on her notes or whatever...it's basically irrelevant.
The syntax in the speech is not her style of speaking, so it leads me to my conclusion that she's completely innocent of any plagiarism charges....and that a campaign staff speech writer is the varlet here, either by deliberate sabotage or willful, sneaky laziness.
The sentences were definity cribbed, unless one has one's head in the sand like an ostrich!
I feel really bad for Melania.
Leni