Committed to Student Success
Tiegerman’s leadership team is driven by a shared commitment to empowering students through language, education, and real-world opportunities. Led by experienced educators, administrators, and specialists, our team brings a wealth of knowledge in special education, speech-language development, and innovative learning strategies. Each member is dedicated to creating a supportive, inclusive environment where students can thrive academically, socially, and emotionally. Through collaboration and forward-thinking leadership, we continue to expand our programs, build meaningful partnerships, and advocate for children with language and learning differences—ensuring that every student at Tiegerman has the tools and support to reach their full potential.
Dr. Ellenmorris Tigerman
Chief Executive Officer
Dr. Ellenmorris Tiegerman is not just the founder and Executive Director of TIEGERMAN; she is its heart and soul. For over 40 years, she has dedicated her life to creating a compassionate and inclusive environment where individuals with disabilities can thrive. Guided by the deeply personal philosophy of “Celebrating Differences, Transforming Lives,” Dr. Tiegerman has built a family of programs that honor the uniqueness of every individual while empowering them to navigate the world with confidence and pride.
Her passion for helping others began early and has remained the driving force of her career. Dr. Tiegerman’s work goes far beyond creating programs; she has spent countless hours connecting with students, families, and educators, ensuring that every child’s potential is recognized and celebrated.
Under her leadership, Tiegerman has become a cornerstone of education, advocacy, and community engagement. Known for her warmth and accessibility, Dr. Tiegerman is as likely to be found listening to a parent’s concerns as she is leading groundbreaking initiatives. Her programs do more than teach—they inspire students to believe in themselves, build confidence, and embrace their unique abilities.
Dr. Tiegerman’s commitment to inclusion has extended to her influential roles in education and public policy. She was invited to serve on Governor George Pataki’s Transition Team for Education (1994), played a pivotal role on the New York State’s 21st Century Schools Committee (1995), and chaired the Parent Involvement Committee for the New York State Early Intervention Coordinating Council (1996). These opportunities gave her the platform to advocate for meaningful change for families navigating developmental challenges.
As a Professor Emeritus at the Derner Institute for Advanced Psychological Studies at Adelphi University, Dr. Tiegerman combined her deep expertise with a hands-on approach to teaching and leadership. She directed the Adelphi University Speech and Hearing Center and founded the Preschool Language Stimulation Program, creating safe spaces where early intervention strategies could flourish.
What truly sets Dr. Tiegerman apart is her ability to connect. Whether mentoring a young professional, collaborating with a colleague, or encouraging a child to take their first steps toward success, her humanity and genuine care shine through. She understands that the work is not just about programs or policies; it’s about people.
Dr. Tiegerman’s legacy is one of hope and transformation. Every child who discovers their voice, every family who finds support, and every educator inspired to make a difference carries forward her vision of celebrating differences and transforming lives.
- (516) 609-2000
Dr. Jeremy Tiegerman
Chief Operating Officer
Dr. Jeremy Tiegerman is a prominent figure in the field of education and psychology, particularly in serving students with developmental disabilities. He currently holds the position of Chief Operating Officer at Tiegerman (formerly known as the School for Language & Communication Development) in the New York City Metropolitan Area.
Dr. Jeremy Tiegerman’s educational background is extensive. He earned his Bachelor’s degree in Psychology from the University of Maryland between 1996 and 2000. He then pursued advanced studies at Hofstra University, where he obtained his Master’s degree, Certificate of Advanced Studies, and Doctorate in School Community Psychology from 2000 to 2005.
In his professional career, Dr. Jeremy Tiegerman has held various roles within the Tiegerman organization. He served as a Psychologist from January 2007 to August 2010, Principal from September 2010 to August 2013, and then as a Director from September 2013 to December 2022. In January 2023, he assumed the role of Chief Operating Officer.
As COO, Dr. Jeremy Tiegerman oversees all of Tiegerman Schools and Tiegerman Community Services.
Dr. Jeremy Tiegerman is also known for his role as the Educational Director at Tiegerman, during the COVID-19 pandemic, when he conducted weekly “State of the Union” addresses from his home, keeping parents, caretakers, and families informed about developments in the Tiegerman community.
In addition to his administrative roles, Dr. Jeremy Tiegerman is a licensed School Building Leader and School Psychologist, certified by the New York State Education Department. He has also currently has a private practice as a licensed psychologist in Syosset, NY.
Dr. Jeremy Tiegerman’s work aligns closely with Tiegerman’s mission of “teaching the extraordinary,” focusing on identifying children with language and autism spectrum disorders early and providing specialized educational programs.
- (516) 609-2000
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Dr. Christine Radziewicz
Chief Compliance Officer
Dr. Christine Radziewicz brings over three decades of experience in speech-language pathology, audiology, and deaf education to her role as Chief Compliance Officer at Tiegerman. A lifelong advocate for children and families, her journey began at Gallaudet University, where she focused on audiology and deaf education through a prestigious federal grant. She later earned her Doctorate in Speech-Language Pathology from Adelphi University in 1985.
Dr. Radziewicz’s passion for teaching and mentoring was evident during her tenure at Adelphi University from 1979 to 1989, where she held multiple roles in the Department of Speech Arts and Communication Disorders. As a professor in the Deaf Education Program, she prepared future educators to work with deaf children and trained sign language interpreters for their vital roles in schools. She also served as Clinical Director of the Hy Weinberg Center, guiding students across all degree levels through their clinical practicums.
In 1989, Dr. Radziewicz joined Tiegerman as Assistant Director, initially overseeing the Evaluation and Treatment Center. Her contributions have been transformative, guiding her through roles as Director, Chief Operating Officer, and now Chief Compliance Officer. Notably, she played a key role in developing Tiegerman’s inclusion program, fostering integrated learning environments where children with language disorders learn alongside their peers.
Dr. Radziewicz’s expertise extends beyond Tiegerman. In 1997, she was selected to serve on the New York State Department of Health Committee for Autism/Pervasive Developmental Disorders, helping to shape clinical best practices for young children with autism. She has also consulted with public school districts, providing professional training for speech teachers and conducting student assessments.
Her commitment to advancing education is reflected in her scholarly work. Dr. Radziewicz has coauthored two influential books with her close colleague, Dr. Ellenmorris Tiegerman: Collaborative Decision Making: The Pathway to Inclusion (1998) and Language Disorders in Children: Real Families, Real Issues, and Real Interventions (2007). These works highlight her dedication to creating meaningful, inclusive educational environments that support both academic and personal growth for children.
At Tiegerman, Dr. Radziewicz continues to innovate and inspire, with a focus on enhancing learning environments and supporting academic success for children in diverse educational settings. Her work is a testament to her unwavering dedication to the field and the families she serves.
- (516) 609-2000
- [email protected]
Lauren Leonardi
Program Director
Lauren Leonardi has worked in various educational and leadership roles at Tiegerman Schools for over twenty years. Her academic background includes a dual Bachelor’s degree in Elementary and Special Education from Cortland and a Master’s in Childhood Education from Hofstra University. In 2009, Lauren pursued advanced studies and obtained an administration degree (School Building Leader) from the College of Saint Rose.
Lauren began her professional career in 2003 as a teacher at Tiegerman Elementary School. In 2009, Lauren continued her education and pursued a degree in educational administration. She worked as Program Coordinator and Principal at Tiegerman High School for 12 years. Lauren took an active role in developing vocational training and post-secondary planning for all of the students who attended Tiegerman High School. Lauren is a strong leader and advocate for the Tiegerman mission to help individuals with language, developmental, and autism spectrum disorders lead productive and successful lives from preschool through adulthood. She has made it her vocation to provide exceptional instruction, education, and support to ensure that the children and adults served achieve their potential to achieve a more independent and prosperous future.
In 2023, Lauren was promoted to Program Director of Tiegerman Schools. She oversees and supervises six schools, including Tiegerman Preschool/Elementary School, Tiegerman Middle School, Tiegerman High School, Tiegerman School at Woodside, Tiegerman Preschool at Far Rockaway, and our newest addition, Tiegerman Preschool at Saint Catherine’s. Lauren is dedicated to creating a supportive atmosphere for students and their families, advocating for best practices in special education, and collaborating with educators to enhance the learning experience.
- (516) 609-2000
- [email protected]
Tiffany Harkless
Program Director, Tiegerman Community Services
- (516) 698-2000 Ext. 821
- [email protected]
Tiffany Harkless is currently the Director of Adult Services for Tiegerman Community Services (TCS). She has worked with Tiegerman Community Services for over 10 years. During her time at Tiegerman she has served as the Corporate Compliance Officer before transitioning to the role of Director of Adult Services. As the Director of Adult Services Ms. Harkless oversees the following programs: Residential, Day Habilitation, Supported Employment, Community Habilitation and Respite. Ms. Harkless has worked in the field of intellectual and developmental disabilities for 29 years. During her professional journey, she has worked in various capacities; Direct Support Professional, Medical Coordinator, Assistant Residential Manager, Residential Manager and Director of Residential Services. During her tenure with Tiegerman Community Services Ms. Harkless has spearheaded new projects, such as development of new homes, expansion of Program Without Walls, Supported Employment, Community Habilitation and worked to enhance service delivery to current and new TCS participants.