Scientifically proven stutter therapy

scientifically proven stutter therapy

The Del Ferro Method

Speak fluent from the first day of the course

The Del Ferro Method is known as a revolutionary training for overcoming stuttering completely. Since 1978, this scientifically proven stutter therapy has been effective for children and adults who are motivated to overcome stuttering.

Thanks to the unique Del Ferro speaking technique, participants experience the ability to speak fluently from the first day of the course. The stutter therapy is distinguished by its focus on both physical diaphragm training and mental support. This results in learning to speak fluently in all everyday situations.

What makes the Del Ferro method unique?

immediate results

Fluent speaking from the first day of the course, immediately boosting self-confidence and helping to overcome speaking anxiety.

since 1978

Pioneer in the application of diaphragmatic breathing against stuttering.

recognition and reimbursement

Several health insurers reimburse stutter therapy in full or partially.

stutter-free life

Ensures a stutter-free life, while speech therapy often focuses on its acceptance.


Suitable for resolving stammering, banter and stuttering in children and adults, both with a severe stuttering problem and occasional stuttering.

scientifically proved

The method is known as a scientifically proven stutter therapy, demonstrating its effectiveness.

13,000 satisfied participants

Proven success with more than 13,000 people worldwide, with hundreds of success stories recorded.

Core principles of Del Ferro stuttering therapy

The Del Ferro Method is based on two fundamental principles: diaphragmatic breathing and self-development. This combination provides a powerful and effective approach in overcoming stuttering:

The Del Ferro method is based on training the diaphragm muscle, which is the primary respiratory muscle. By making the diaphragm move fluidly and correctly while speaking, students will speak fluently from the first day of the course.

In addition to the diapgram training, the Del Ferro Method also includes an important mental aspect. Self-development focuses on overcoming speaking anxiety, building self-confidence and changing negative thought patterns into confident behaviour. This is essential for continued success.

These two principles are combined in a holistic approach. Participants learn not only how to speak without stuttering, but also how to be mentally stronger in their communication. This creates lasting change and a profound impact on participants’ overall quality of life.

Unlock fluent speech: Discover the success of our course with the Del Ferro Method

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5-day course in Miami

Over these past 5 days my life has changed

Our international course in Miami, Florida was a big success. After years of fruitless speech therapy our students have been searching for help in overcoming their stuttering. With the Del Ferro Method, they finally found a technique that enables them to speak fluently and take back control of their speech. 

The Del Ferro Method: step by step

The Del Ferro Method is a carefully structured process that focuses on overcoming stuttering through concrete steps. Here’s how it works:

1 - Awareness and control of breathing

The method starts by teaching the diaphragmatic breathing technique. Students will learn how to train their diaphragm muscle, which is essential to speak fluent.

After mastering the diaphragmatic breathing technique, students are trained to apply it immediately while speaking. From the first day of the course, this technique leads to the complete elimination of stuttering, allowing students to speak fluently.

During therapy, participants practise speaking in different situations within a safe and supportive group environment, increasing self-confidence and reducing speaking anxiety.

The course also focuses on self-development to address negative thoughts and fears, promoting a positive self-image and increasing self-confidence.

The Del Ferro method is very practical as it emphasises practice in everyday situations. Training is given in all possible speaking situations in which stuttering may occur. Consider, for example, learning to speak fluently in a group, giving a presentation, talking on the phone and reading aloud.

The strength of the method is that when applied, stuttering is impossible. Thus, students learn to speak fluently during any speaking situation.

Through this structured approach, the Del Ferro method provides a clear path to fluent and confident speaking, effectively and sustainably overcoming stuttering.

Students confirm the effectiveness of the Del Ferro Method

Every two years, the results of the Del Ferro Institute students who have participated in the satisfaction survey are compiled. This makes it possible to accurately measure the impact of the Del Ferro method on stuttering and make improvements where necessary. The latest survey, conducted over the period 2020 – 2022, provided valuable insights thanks to the contributions of 480 respondents.

The results of this study are remarkable: a significant majority of 93% of participants reported a moderate to intense degree of stuttering before the start of the course. After completing therapy, 92% of respondents reported a marked improvement, as they no longer stuttered.

Before the stutter therapy

moderate to intense stuttering 93%

After the stutter therapy

speaking fluent 92%

For stuttering therapy: moderate to severe stuttering


After stutter therapy: fluent speaking


In addition to the physical improvements, the research also shows significant progress in self-confidence and the reduction of speaking fears. Before the start of the course, 82% of the participants felt insecure. This uncertainty transformed into an increased self-confidence for 62% of the students after completing the course. At the Del Ferro Institute, overcoming stuttering goes hand in hand with addressing mental challenges so that it leads to speaking confidently and without fear.

Before the stutter therapy

feelings of insecurities 82%

After the stutter therapy

increased self-confidence 62%

Before stutter therapy: feelings of uncertainty


After stutter therapy: increase in self-confidence


The research further emphasized that 88% of students struggled with speaking anxiety prior to the course. Remarkably, after completing the course, 89% of students experienced a significant reduction or complete elimination of this fear.

These results underline the effectiveness of the Del Ferro Method and confirm that a sustainable solution for stuttering is within reach for almost everyone.

Before the stutter therapy

experienced fear of speaking 88%

After the stutter therapy

reduction or elimination of speaking anxiety 89%

For stutter therapy: perceived speech anxiety


After stutter therapy: reduction or elimination of speaking anxiety


Tribute to the founder of scientifically proven stutter therapy

In 1978, Len Del Ferro, an internationally renowned American tenor, laid the foundations for the pioneering Del Ferro Method. After an impressive international career in opera, he settled in Amsterdam as a vocal pedagogue. He became an influential figure in the Dutch music world by teaching many well-known Dutch artists.

Len Del Ferro was not only a master of music, but also a pioneer in the world of breathing and mental coaching. His innovative approach marked him as the first of its kind in the Netherlands.

Del Ferro’s biggest breakthrough came in the field of stuttering. In the late 1970s, he discovered that stuttering had a physical cause. A discovery triggered in part by his observation that people who stutter can sing fluently but have difficulty speaking. This was a revolutionary insight that went against the prevailing beliefs of the time.

Many people with a stuttering problem were told to learn to live with it.

Indeed, it was thought that stuttering was mainly a psychological problem. Del Ferro’s work has fundamentally changed this view.

The diaphragm muscle is normally the silent motor behind our breathing, while in stuttering that muscle appears to make uncontrolled movements. This insight from Len Del Ferro offered not only a new perspective, but also a concrete solution. By training and controlling the diaphragm muscle, you can experience a significant improvement in your speech.

Len Del Ferro is the founder of the Del Ferro Institute

For more than a decade, Len Del Ferro helped hundreds of people overcome their stuttering. Among them was Patrick Wijdenes, one of our current teachers, who had the privilege of learning directly from Del Ferro. This direct transfer of knowledge forms an essential basis for Patrick’s lessons, in which he applies the powerful techniques of the method.

After Len Del Ferro’s death in 1992, his innovative work was diligently continued by his daughter Ingrid. She was heavily involved in his work and played a crucial role in the further development of the scientifically proven stutter therapy. Under her leadership, the Del Ferro method has evolved and is recognised and respected worldwide as an effective treatment for stuttering.

The Del Ferro method is a scientifically proven stutter therapy

Besides solving stuttering, the Del Ferro Method has the added benefit of teaching participants an extremely efficient breathing technique. This not only improves breathing, but also stamina and overall condition and fitness. The result is reduced lactic acid levels in the blood, leading to less fatigue and faster recovery after exercise.

The method also offers relief for burnout complaints, hyperventilation and other breathing problems.

The innovative approach of the Del Ferro method has been extensively scientifically researched and confirmed. Neurologist Dr Van Hemert was the first to test Len Del Ferro’s hypothesis. His research showed that uncontrolled movements of the diaphragm muscle occur in stuttering, which disrupts airflow and leads to stuttering.

That finding has been supported by other leading scientists, including neurosurgeon Dr De Grood and Professor Macklem, an authority on pulmonary physiology. Their studies confirmed that smooth airflow created by controlled diaphragmatic movements is essential to prevent stuttering.

The neurologist Dr. J.C.J. van Hemert tested Len Del Ferro’s hypothesis in 1978. Van Hemert’s scientific research shows, with the help of X-rays and others, that the diaphragm muscle makes uncontrolled movements during stuttering.

Professor Peter T. Macklem of McGill University in Montreal, Canada, was one of the most renowned specialists in the field of pulmonary physiology and the diaphragm. He confirmed Len Del Ferro’s hypothesis.

Ingrid Del Ferro: The power behind overcoming stuttering

Ingrid Del Ferro has led the Del Ferro Institute for more than three decades. Her expertise and dedication are the driving force behind the institute. Together with a team of expert stutter therapists, she ensures that everyone can overcome stuttering for good with the scientifically proven stutter therapy. Under their guidance, thousands of people have already learned to speak without stuttering from the first day of the course.

Ingrid’s expertise on stuttering has made her a sought-after expert in the media, both nationally and internationally. From appearances on Dutch and German television to interviews by CNN and BBC, Ingrid shares her knowledge and insights on stuttering with a wide audience.

Under her leadership, the Del Ferro Method continues to evolve and gain worldwide recognition as an effective treatment for stuttering. With her pragmatic result-oriented approach and empathetic attitude, Ingrid has positively changed many lives.

The proven Del Ferro method makes people stutter-free

Experience the Del Ferro Method for yourself in one of our stuttering courses

Meet our pioneering programmes at the Del Ferro Institute, where we integrate the Del Ferro Method into our training courses. These programmes are specially designed for people of all ages, both children and adults. More than 13,000 people have now attended one of the training courses.

It’s never too late for a stutter-free life. Speak stutter-free from the first day of the course. The course takes place in a small group at our training location in Amsterdam. Thousands of adults have gone before you.

Live your dream without stuttering! And that from the very first day of the course. The course takes place in a small group at our training location in Amsterdam. Thousands of young people have gone before you.

Give your child a stutter-free future. Stutter therapy takes place in a small group at our training location in Amsterdam. From the first day of the course, your child will speak stutter-free. Thousands of parents and carers have gone before you.

Experience the Del Ferro Method for yourself in one of our stutter therapies

Customised stutter therapy for adults and children, offered at our training venue in Amsterdam, at a location of your choice or in the comfort of your own home with personal one-to-one guidance. Speak stutter-free from the first day of the course.

Stutter therapy is offered entirely online via interactive video sessions, with all lessons taught live by one of our stutter therapists. Speak stutter-free from the first day of the course.

Join the thousands of people who have already benefited from Del Ferro stutter therapy and start your journey to a stutter-free life today!

Plan je gratis online informatiegesprek over wat de Del Ferro methode voor jou kan betekenen

Plan je gratis online informatiegesprek over de therapie die Geertruida volgde

Geertruida stottervrij met Del Ferro

Voetballer Lutsharel Geertruida spreekt stottervrij in zijn documentaire 'Kind van Zuid'!

Mogelijk gemaakt door Del Ferro. Volg exact dezelfde stappen en word ook stottervrij! We vertellen je er graag alles over:

Del Ferro bij Humberto

Heb je Ingrid en Dennis gehoord bij Humberto op NPO Radio 1?

Volg exact dezelfde stappen als Lutsharel Geertruida en word ook stottervrij!