Communication between business process modellers and domain experts can be aided by business process models. However, this communication can become difficult if the domain experts have no deep knowledge of the formal modelling language and the processes include variable elements, i.e. when several ways exist to reach the goal of a process. We propose to support the communication by means of a lightweight and rather informal language. It is based on building blocks that express different patterns of variability. In addition to discussing these patterns, we also show how they can be expressed in the formal modelling languages BPMN and CMMN. This allows to communicate on an informal, but easy-to-understand level without loosing the possibility to create computer-interpretable formal business process models.