Incorporation of mindfulness techniques, regardless of instructional discipline, is a strategy that has more than emerging evidence. A systematic review of studies of mindfulness training for students and adults with developmental disabilities found significant effects on a range of areas, documenting reduced aggression and anxiety and increased social skills and academic performance (Hwang & Kearney, 2012). Many programs such as Mindful Schools are being implemented school-wide, teachers are being encouraged to practice mindfulness and leading treatment practices incorporate activities such as Yoga classes.
For our students who struggle with managing their own thoughts, and so are led in tangential/oppositional/anxious/dysregulated directions impacting their communication, mindfulness can be incorporated in small ways. Books, videos and audio files focused on awareness of and strategies around thinking can be very engaging, and also serve as language activities by virtue of eliciting descriptive and metacognitive language.
I highly recommend the Cosmic Kids YouTube channel for a start for short meditation activities for your young students. The Zen Den series are short, beautifully produced, visual meditations focused on a variety of calming thinking strategies. I have field-tested these with a range of groups, with great responses from both girls and boys. The fact that the clips are on YouTube makes a great connection to home, as meditation is meant to be done regularly, even for short periods of time.
Even if that carryover is not achieved, clips such as Master the Monkey establish a concrete connection and vocabulary for an abstract concept: our mind can be like a hyperactive monkey and we can practice strategies to keep it present:
Movies in My Mind presents a fun visualization exercise for which you can conduct a language-based debriefing after the fact: "What did you see on the other side of that door?"
Getting Wanty discusses a specific situation of wanting something in a store, but can be applied to many other situations involving "JustMe" vs. Thinking of Others and social behavior (see the work of Social Thinking®).
See also the great Yoga Adventures videos that put yoga in the context of settings and "stories," again offering connections to language activities and themes.
Hwang, Y, & Kearney, P. (2012). A systematic review of mindfulness intervention for individuals with developmental disabilities: Long-term practice and long lasting effects. Research in Developmental Disabilities. 34, 314-326