Trump used to be more articulate. What could explain the change?

It was the kind of utterance that makes professional transcribers question their career choice:

“ … there is no collusion between certainly myself and my campaign, but I can always speak for myself — and the Russians, zero.”

When President Trump offered that response to a question at a press conference last week, it was the latest example of his tortured syntax, mid-thought changes of subject, and apparent trouble formulating complete sentences, let alone a coherent paragraph, in unscripted speech.

He was not always so linguistically challenged.

STAT reviewed decades of Trump’s on-air interviews and compared them to Q&A sessions since his inauguration. The differences are striking and unmistakable.