There are several techniques that can be used to promote communication in a Scrum team, like for instance the Dialogue Sheets that are proposed by Allan Kelly for retrospectives. In this blog post, Alan Dayley discusses how silence is a powerful tool for management and the need for constructive conflict.
Being silent, the ScrumMaster give the team time to think and create space for solutions to emerge. This especially true as any team includes a number of members who are perfectly happy to come to a meeting and not say a word. The post proposes a scenario to start a retrospective in a silent way that will allow these people to express themselves. This lead to an increase in trust between the team members and could help solving those hard conflicts where people need to talk.