All pupils are likely to be expected to join in a performance, whether it is a small-scale presentation to the class, an assembly presentation, or a school production.
The curriculum emphasises these skills and they are formally assessed for GCSE English, so experience should be built up over the years. The teacher should judge all the children, including the child who stammers, who want to speak/ play a role, on their merits as performers in that role. There are a number of famous performers who do stammer who started off in school productions. See also Performances: Success stories
Some children who stammer may not do so when performing, but, even if they do, that should not automatically exclude them, as they may possess other skills that allow them to play that role effectively. Children do not usually stammer when singing and may enjoy the experience of being fluent. When a pupil who stammers is able to perform in another medium, in dance, mime or musical items for instance then that should be encouraged. Such an opportunity will boost the self-esteem of children who stammer and encourage their sense of self worth in relation to the others.
Young children who are not self-conscious about their stammer may join in these quite naturally, but older ones may be very anxious. The teacher should encourage the child to join in with a 'step by step' approach, where initially talking is done with other children. The child speaking on the video clip found that talking with another child helped her a lot and she seems to be building up confidence so later solo talking may be tried. Initially, this can be in a supportive situation, talking to one person, then to a group of friends for example.
Progress is never linear, and the teacher may need to use the same strategies as the child gets older, becomes more self-aware and is faced with more demanding oral tasks.