About Us

Sarah Yost, M.A. CCC-SLP

Sarah has over 15 years of experience designing treatment plans, administering speech-language pathology evaluations, providing speech therapy, documenting provisions, and collaborating with healthcare teams to provide the best therapy services for patients and patient's families.

Before starting Defining Voice, Sarah worked for several private practices, public, and private schools in the Bay Area. She developed many great relationships with Special Education Directors, Pediatricians, and service coordinators that play pivotal roles in the lives of children with special needs.

Sarah started her own practice to establish a new standard for speech therapy by including families in therapy sessions. By involving family members Sarah not only accelerates the progress made by her patients, but she's able to connect with patients and their families as a team.


CA SLP License: SP 17634

CA Teacher License: 080012159

NPI: 1376954644

Independent Coursework

  • Integrating a Language Approach to the Common Core Standards: Practical Strategies for Relevant, Evidence-Based Instruction and Intervention

  • Effective Intervention for Oppositional and Defiant Behaviors Strategies to Rewire the Brain to Improve Behavior and Development

  • Conquering R: Effective Evaluation and Intervention Procedures

  • Play-Based Treatment: Basic Strategies for Exceptional Instruction

  • Adolescents with Autism: Writing for Success!

  • A-Z: Essential Treatment Components for Severe Phonological Disorders

  • Understanding Hearing Loss for Speech-Language Pathologists

  • Special Education Eligibility: When is Speech-Language Impairment a Disability?

  • The 3:1 Service Delivery Model

  • Childhood Neurology

  • Childhood Apraxia of Speech Assessment, Treatement, and Early Literacy Skills

  • Comprehensive Assessment of Foreign Accented English

  • What Child Language Research May Contribute to the Understanding and Treatment of Stuttering

  • The Common Core State Standards

  • Aspects of Literacy Development in Preschool and Elementary School Age Children

  • The Bridge of Vocabulary: Strong Research Leads to Good Practice

  • Incorporating Social-Emotional Learning Into Speech-Language Intervention

  • Treatment of Speech Sound Disorders

  • Remediating Difficult Sounds

  • Comprehensive Assessment and Intervention Using the DIR/Floortime Model

  • Motor Development and Sensory Integration

Sarah Yost, M.A. CCC-SLP, Director of Speech Therapy

Michelle Belleville, M.S. CCC-SLP

Michelle received her Master of Science in Speech-Language Pathology from Midwestern University-Downer’s Grove. In her undergraduate career, at the University of Iowa, she received her Bachelor of Arts in Communication Sciences and Disorders and received her American Sign Language and Deaf Studies Certificate. Prior to becoming a Speech-Language Pathologist, Michelle worked as a camp counselor at a Stuttering Camp at the University of Iowa and then a one-to-one aide in a therapeutic day school with children primarily diagnosed with Autism Spectrum Disorders (ASD). Following graduate school, Michelle worked as a SLP in two charter schools in Chicago. She has worked with culturally and linguistically diverse students from kindergarten to eighth grade and has extensive experience administering assessments to ELL students. She is intimately familiar with the educational model of Speech Therapy having driven many IEP meetings in collaboration with parents, teachers, and therapists. Currently, Michelle treats and assesses multiple communication disorders using evidence-based practice. Michelle continues to have a special interest in pediatric fluency, AAC, apraxia of speech, and autism spectrum disorders. Michelle is currently a supervisor for Speech-Language Pathology Assistants (SLP-A) at Defining Voice.

CA SLP License: SP 26274

NPI: 1164947594

Independent Coursework

  • 5 Mistakes to Avoid in Data Collection

  • Got R Problems? A Phonetic Approach to R Remediation

  • How to Choose Educationally Relevant Mobile Apps

  • Practical Approaches to Fluency for School-Aged Students

  • Social Thinking in the Early Years: A Case Study

  • Utilizing Therapy Tools for Diverse Student Needs

  • Why Don't They Do That in Class? Easy Carryover with Curriculum-Based Therapy

  • AAC TouchChat App

  • Effective Therapy Ideas for Targeting Social Skills with Older Students

  • Childhood Apraxia of Speech (CAS): Treatment Techniques

  • Treatment Options for Childhood Apraxia of Speech (CAS)

Michelle Belleville, M.S. CCC-SLP, Speech-Language Pathologist

Annika Stark, M.A. CCC-SLP

Annika has been interested in the field of speech-language pathology since she was fourteen years old. As the oldest of five, she has always enjoyed being with children. Annika received her Master of Arts in Speech-Language Pathology from Utah State University. She received her Bachelor of Science in Communication Disorders from Brigham Young University with Magna Cum Laude honors. She completed an externship with an ENT center where she gained experience with voice, swallowing, and dysarthria. As an intern in the public schools, she gained experience working with middle school and preschool students. At a private practice internship, Annika worked predominantly with young children with autism. Annika loves being a part of the team at Defining Voice!

Annika Stark, M.A. CCC-SLP, Speech-Language Pathologist

Carly Shless, M.S. CF-SLP

Carly received her Master of Science in Medical Speech-Language Pathology at the University of Washington in Seattle and her Bachelor of Science in Speech-Language Pathology at the University of Illinois at Champaign-Urbana.


Carly has experience in using evidence-based practice in evaluating and treating a wide variety of patients across the lifespan, but she especially enjoys working with the pediatric population! Carly has completed externships in multiple pediatric private practice settings. Through these externships, she has gained experience in working with children with autism, as well as other complex communication needs. Carly has also completed an externship in an acute care setting, along with an adult-focused, voice rotation.


Carly enjoys working closely with patients and their families, as well as providing fun, play-based therapy to her pediatric clients! Carly’s interests include autism, augmentative and alternative communication, articulation, apraxia of speech, and fluency.

CA SLP License: RPE 12926

NPI: 1306324603

Carly Shless, M.S. CF-SLP, Speech Language Pathologist Clinical Fellow

Sharon Serper, M.A. CF-SLP

Sharon received her Master of Arts in Speech Language Pathology and Bachelor of Arts in Speech and Hearing Sciences from The University of Iowa. She is a bilingual English-Russian speaker who has experience working with culturally and linguistically diverse individuals. Sharon has completed externships in several outpatient clinics and worked with many diverse adult and pediatric clients. As a graduate student, she participated in a multidisciplinary autism diagnostic clinic, in which she collaborated with a team to help families of children with various communication needs. Sharon is passionate about working with children and enjoys working closely with clients and their families. Her areas of interest are augmentative and alternative communication, autism, articulation, and early intervention. 

Sharon Serper, M.A. CF-SLP, Speech-Languge Pathologist Clinical Fellow

Janet Rios, B.S. OTR/L

Janet has over 15 year of experience working with children and adults. Janet specializes in treating children with feeding difficulties, sensory processing differences, fine and gross motor delays, visual perceptual delays, handwriting deficiencies, and motor development delays. In previous positions Janet has supervised more than 20 occupational therapists and managed occupational therapy programs for private clinics and public schools. Janet is a member of the American Occupational Therapy Association and a member of the National Board for Certification in Occupational Therapy.

CA License: OT 1228

NPI: 13944743

Independent Coursework

  • The DIR Approach to Pediatric Feeding

  • SOS Approach to Feeding

  • Visual Vestibular Integration

  • Handwriting Without Tears

  • Keyboarding Without Tears

  • Interactive Metronome Certification

Janet Rios, B.S. OTR/L, Occupational Therapy Director

Amy Schendel, M.S. OTR/L

Amy earned her Master of Science degree in Occupational Therapy from Sacred Heart University and has been practicing for over eight years specializing in Pediatric Occupational Therapy. She has worked with children and adults with a variety of neurological, cognitive, and physical challenges in outpatient settings. Amy has experience working in educational settings as well as medical centers and hospitals. In the past, Amy has supervised Occupational Therapy Assistant and directed clinical OT students performing fieldwork as part of their curriculum.

Before Amy started her career as an Occupational Therapist, she was an ABA therapist at Nationwide Children's Hospital. Amy is also a registered Yoga Instructor with over 200 hours of practice and a dance teacher for more than 10 years.

CA SLP License: OT 14051

NPI: 1598060931

Independent Coursework

  • Dyslexia, Dyscalculia & Dysgraphia: An Integrated Approach

  • Supporting Inclusion Through the Introduction of Yoga in the Classroom

  • An Executive Functioning View of Proof Impulse Control, Motivation, and Self-Regulation

  • Yoga for Therapeutic Rehabilitation

  • Evidence Based Treatment for Hand, Wrist & Elbow Injuries

  • Sensory Processing Disorder in Children 0-3 Born Prematurely

  • Effects of Stability Balls on Children's On-Task Behavior and Academic Achievement

  • Best Practices in Cognitive and Executive Functioning to Enhance Participation

Amy Schendel, M.S. OTR/L, Occupational Therapist

Julieta Perea, B.A. SLPA

Julieta ("Julie"), received her B.A. in Communicative Disorders from San Jose State University and holds a state license in Speech and Language Pathology Assisting. Julie has over six years of experience providing individualized and social group speech therapy in private clinical settings including early intervention clinics. Julie has experience providing individualized, and group, speech therapy in the school setting, and working in early intervention programs. She has been trained in the SCERTS model for children diagnosed with Autism and the Slingerland Multi-sensory Structured Language Approach, which helps students struggling with reading, writing, and spelling skills. Julie is also fluent in Spanish. Julie has been trained to coach families on how to implement the skills they learn in every session into their home environment, and collaborates with other therapists (OT, ABA, Psychologist, etc.) to meet each child’s goals with consistency. Julie has worked with an extensive number of speech and language disorders. Her patience, collaboration, support, and experience are only some of the qualities that make Julie an amazing therapist. In her free time, Julie enjoys spending time with her family and friends, drawing, and dancing!

CA SLP License: SPA 2071

NPI: 1649620428

Independent Coursework

  • The Power of Play: Effective Play-Based Therapy and Early Intervention

  • AAC Strategies for Promoting the Development of Communication for Individuals with ASD

  • The Habits of Happy People

  • Introduction to SCERTS

  • Slingerland training program, introductory level

  • Parent coaching and early learning

  • ASL level I

Julieta Perea, B.A. SLPA, Speech-Language Pathology Assistant

Heather Diemel, B.S. SLPA

Coming soon!

Heather Diemel, B.S. SLPA, Speech-Language Pathologist Assistant

Jayme Jones, B.A. SLPA

Jayme received her B.A. in Early Childhood Development from Brandman University. After working in positions across the educational spectrum she discovered her passion for working with children with special needs. It is then that she began her journey of becoming a Speech-Language Pathologist. She received her certificate of preparation for advanced studies in Speech-Language Pathology from California State University, Northridge (CSUN) and holds a state license in Speech-Language Pathology Assisting. Currently, she is pursuing her Master of Science degree in Communication Disorders and Sciences through CSUN to become a licensed Speech-Language Pathologist. Throughout her studies she had the opportunity to work in the school and private practice setting treating children and adults with a diverse set of needs including expressive and receptive language, articulation, voice, fluency, apraxia, aphasia, dysphagia, dysarthria, auditory comprehension, and cognitive communication using an evidence-based treatment approach. She has also been a Program Specialist at Autism Partnership where she received extensive training in the application of Applied Behavior Analysis (ABA) and Discrete Trial Teaching (DTT) implemented primarily with children, of all ages, diagnosed with autism spectrum disorder. Her special interests include childhood apraxia of speech, expressive/receptive language disorder and autism spectrum disorder. She is passionate about the field of communication disorders and strives to equip each individual with the tools to achieve his or her own potential.

Jayme Jones, B.A. SLPA, Speech-Language Pathologist Assistant

Tina Melendez, CPC

Tina is the conductor of Defining Voice's back office. With previous experience coordinating for Ophthalmologists and Physicians and with her medical billing certification, Tina is intimately familiar with our billing process and is able to answer your day to day questions. Tina is also certified as a Certified Professional Coder (CPC) by the American Academy of Professional Coders.

AAPC Certification: 01420059

Tina Melendez, CPC, Back Office Coordinator

Kristy Batista

Kristy has over 10 years front office experience working with Stanford Hospital. She is also a Certified Medical Assistant graduate from Merced College Career Advancement Academy. Kristy is well equipped to answer your day to day questions and help you navigate your options as a patient.

Kristy Batista, Patient Services Coordinator

Alejandra Rico Duarte

Alejandra is a certified Medical Administrative Assistant and has previously work in several medical office settings. Her energy and can-do attitude maker her an amazing Coordinator. She also speaks Spanish and frequently helps us translate for our Spanish-speaking families.

Alejandra Rico Duarte, Patient Services Coordinator

John Yost, M.S. EE


John Yost, Everything Else

Please reload

All staff at Defining Voice...

  • have been screened by the FBI through a DOJ background check,

  • screened for Tuberculosis, and

  • received CPR certification.


All therapists at Defining Voice...

  • hold a license from the Medical Board of Speech-Language Pathology of California,

  • participate in a minimum of 24 hours of continuing education classes per year, and

  • work in close collaboration with each other to identify the best approach for each patient.