Just wanted to jump on here and steer you over to Technology in Special Education. If you aren't familiar, their website is a great reference for all things technology. They have a 'Free App of the Day' feature that I constantly use! They also have an Apps by IEP goal list!
I wrote a guest post aimed at parents of children who have expressive language delays. I listed some apps and some direct ways to use the apps to encourage first words in toddlers. You might want to share these apps and ideas with parents of children on your caseload!
What other apps are you using for these young children?