My son was using TalkTools products since he was about 4 months old until he was 2 years old.
Any other tools that are recommended for kids with Down Syndrome?
These behavior can develop as children get older. In my class on Autism, I describe many factors that can contribute to behavioral challenges, sensory-motor challenges and moving forward in therapy.
First and foremost a predictable schedule with built in rewards is critical. Rewards need to be very frequent.
Secondly many kids need a sensory warm up. Consult with an OT/PT that specializes in sensory integration. Whole body movement, massage, music and sensory methods may be helpful prior to oral exercises.
Finally, without seeing your child myself I cannot recommend specifics; however at TalkTools not only do we support our work, but the work of Pam Marshalla, Debra Beckman and Diane Bahr, all have oral motor programs. I suspect the program may be too routine, so adding some massages, feeding programs and a more reinforcers may do the trick.