Basic conversational skill that teaches children that a conversation is a turn-taking activity that includes listening, attention and respect for others.
Your mum is talking to your dad and you want to ask to watch a film on the TV
Be patient and wait until the right moment to ask for something. You could find something else to do until your mum and dad have finished talking. Once it is clear they are available, you should say ‘excuse me, can I ask you something?’ followed by your question you want to ask.