JD Vance fumbles 'proficiency' while saying 'We made English proficiency mandatory'. US Vice President JD Vance stumbled while pronouncing “proficiency” as he said "English proficiency was made mandatory" for commercial driver's licences. A video of Vance struggling with the word during a midterm campaign rally has gone viral on social media. "The irony speaks for itself," a person reacted to the video. "You can't speak the language correctly yourself," said another.