segments of him bumbling and use it to show Trump is under cognitive decline.
The language abilities of Trump had massively declined from his speaking in the 1980s.
The reality is both candidates were old men on the decline. Fox News is just recycling attacks used on Trump's cognitive abilities from a couple years ago.
2017 article
https://www.statnews.com/2017/05/23/donald-trump-speaking-style-interviews/
2018 article
https://www.theatlantic.com/health/archive/2018/01/trump-cog-decline/548759/