choke on (one's) (own) words

To have particular difficulty saying something, especially because one is overwhelmed with emotion. The retiring broadcaster gave a tearful speech at the end of his last show, choking on his words as he tried to express his gratitude to all his fans and supporters. She was so overcome by anxiety up on that stage that she stammered and choked on her own words throughout the entire presentation. I didn't write my own wedding vows because I knew I would be emotional during the ceremony, and I didn't want to choke on my words.