I recently asked a high school coach why some teams outperform other teams when the pool of athletes seem so similar. "It's because the coach was able to build and 'sell' a program to which the athletes adhered. The students did the scheduled workouts (versus adding their own or completely ignoring the workout schedule), worked out as a team and worked as a team, supported one another during times of difficulty and celebration, and they built on their knowledge. But, in the end, it's because of the coach. The coach holds it all together."
I share that because I think the story is analogous to the embedding of UDL within any educational environment. You need that singular leader who can focus energy on building a support system for teachers which includes training, teacher-specific examples, and the ability to share ideas/question/concerns. This person also needs to gain the support of the school district leaders (or the school leaders if the implementation is at an individual school level) and continue to "sell" the benefits and outcomes related to UDL.
A good coach rarely works alone. Similarly, quality leadership is often marked by one's ability to recruit other individuals whose skills match the needs of the endeavor. To successfully embed UDL, the person or persons who bring the idea to the district/school need to identify others who can help put into action trainings, the creation of teacher-specific examples, and the establishment of a teacher-focused collaborative environment (virtual, face-to-face, or both). In the school setting, I believe that last component is the most challenging.
The act of sustaining begins on day one. If you're not truly committed to sustaining the effort, why are you beginning? So, instead of dillineating between embedding and sustaining, the leader(s) move forward with a defined vision. Within that vision, the leader(s) continue(s) to promote UDL, bring in information, and provide multiple examples and input on how it is an effective framework. The other individuals within the UDL camp continue to create, train, support, receive feedback, and improve on their offerings.
Scaling up also occurs at both of these levels. As UDL becomes a recognized guide for curricular design, educators are more likely to accept that UDL can guide all other curricular decisions. However, it takes the leader(s) to establish this connection.
The level of UDL-specific direct instruction/training will continue to evolve with district initiatives, state level mandates and federal changes. Though the instruction and training might change to meet the requirements placed on teachers by these entities, UDL remains the constant. The framework provides a stability to which teachers can connect and rely.