To speak with difficulty, repeating words or sounds because of being nervous or unsure.
When someone stammels, they might feel embarrassed or worried about speaking.
Examples:
He stammels when he talks to new people.
She stammels her name when she is asked.
The little boy stammels 'I want my mommy' when he is scared.
The cat stammels when it sees the big dog.
I stammel and stammer when I have to speak in front of a lot of people.
The robot stammels its words because it is broken.