Speak at a slightly slower pace, and allow time between sentences for the learner to process the information and respond. This might seem like an uncomfortable pause to you, but it is important for helping the learner to communicate.
Avoid speaking sharply or raising your voice.
Use short, simple sentences.
Try to communicate with the learner in a conversational way, not question after question (it can feel like an interrogation).
Try to laugh together about misunderstandings and mistakes – it can help. Humour can help to bring you closer together, and may relieve the pressure. However, be sensitive to the learner and don’t laugh at them.
Include the learner in conversations with others. This may be easier if you adapt what you say slightly. Being included can help a learner’s with low numeracy/literacy skills/confidence to keep their sense of identity and feel they are valued. It can also help to reduce feelings of exclusion and isolation.