Smart homes are a promising infrastructure to support assistive services that can prolong independent living of older adults. However, smart homes are mostly developed using a technologycentered approach, raising challenges for users to comprehend the purpose of smart home services and anticipate their behavior. These challenges are more acute when services are to be deployed in homes of older adults, preventing the expert knowledge of their caregivers to be leveraged. This paper presents a user study that assesses the comprehensibility of an end-user language, named Maloya, dedicated to developing assistive services. Participants (9 professional caregivers) are presented with services written in Maloya and must determine whether they detect scenarios of daily living. Our results show that Maloya is well-understood by participants; they successfully determine whether a service detects a scenario (success rate of 94%) and substantiate their answers with consistent explanations. As such, Maloya should be effective in empowering caregivers to select appropriate services for their care-receivers and to accurately anticipate the service behavior.