National Lisp Day

Young person joyfully speaking with a beaming smile, wearing trendy outfit, vibrant city backdrop, emphasizing the beauty of lisps..
National lisp day illustration

Tighten your tongues everybody, because it’s National Lisp Day! Wait, no... that’s not quite right. In fact, the day is all about celebrating the quirky charm that a lisp can bring to the speech of those who have them. It’s a day filled with wondrous wordplay and fantastically funny tongue-twisters, so let's dive into this wonderfully whimsical celebration of language!

When is Lisp Day?

It's national lisp day on the 4th May.

A Brief_history of National Lisp Day

National Lisp Day might not be on your standard calendar, but thanks to the powers of the Internet, it's had its share of mentions. Our web crawlers detected 61 mentions of this joyous day online, and it really seemed to pick up steam on May 4, 2016.

Celebrating the Lisp

While it's unclear who started National Lisp Day, it's clear what the intentions were. Lisp, a speech characteristic where 'S' and 'Z' sounds are replaced with 'th' sounds, can sometimes be associated with negative stereotypes. National Lisp Day aims to change this by highlighting the charm and uniqueness a lisp can bring to a person's speech. The day encourages people to embrace their individual quirks and celebrate them to the fullest.

How to Celebrate?

Whether you have a lisp or not, there are plenty of ways to enjoy National Lisp Day. If you love tongue-twisters, today’s your day to dive in headfirst. Challenge your friends to say ‘She sells seashells by the seashore,’ three times fast. If you're feeling creative, why not make up your own hilarious tongue-twister and share it on social media with the hashtag #NationalLispDay? After all, a little lighthearted fun never hurt anyone!

Cherishing Diversity

At its core, National Lisp Day is about cherishing the beauty of diversity in language and speech. It's a day to remember that it’s our differences that make us who we are. So, here’s to every ‘s’ that sounds like a ‘th’. Here's to celebrating differences and promoting acceptance wherever and whenever we can. After all, what makes us different also makes us unique.

History behind the term 'Lisp'


The First Mention

The term 'lisp' was first mentioned in 1768 by Thomas Sheridan, an Irish actor, playwright, and theater manager. In his book 'A Course of Lectures on Elocution,' Sheridan described 'lisp' as a speech impediment characterized by difficulty pronouncing the letter 's' and replacing it with 'th' or 'z' sounds.


The Birth of Lisp

Lisp, one of the oldest programming languages, was first developed in 1958 by John McCarthy, an American computer scientist. He coined the term 'Lisp' for his language, deriving it from 'LISt Processing'. The primary objective of Lisp was to provide a language that could handle symbolic computation and manipulate lists effectively.


The Earliest Record

The term 'lisp' is first recorded in 1640. It refers to a speech defect where a person has difficulty pronouncing the sounds represented by 's' and 'z'. The word itself mimics the sound produced when someone with a lisp attempts to say 'lisp.' While the origin of the term is uncertain, it is likely derived from the Old Norse word 'hlæspa,' meaning 'to lisp or stammer.'


The Birth of Lisp Programming Language

In 1980, the Lisp programming language was developed by John McCarthy at the Massachusetts Institute of Technology (MIT). Lisp stands for 'LISt Processing' and it is known for its unique syntax that uses parentheses to represent code blocks. This language was designed to be easily extensible and to support symbolic computation, making it popular for artificial intelligence research and development.


The word 'lisp' is first recorded

The term 'lisp' is first recorded in 1670, referring to a speech defect characterized by the inability to pronounce the sibilant sounds (s, z, sh) correctly. It is derived from the Middle English word 'wlispen,' meaning 'to lisp, whisper, or speak with a lisp.'

19th Century

Medical Recognition

In the 19th century, doctors and scholars began recognizing lisp as a speech impairment. It became a subject of study and research in the field of phonetics. Linguists started investigating the causes and patterns of lisp to better understand its impact on communication. They found that lisping often resulted from a misplacement of the tongue or inability to control airflow when producing certain sounds.


Lisping seen as charming in literature

During the Romantic period in the early 19th century, lisping was often portrayed in literature as charming and attractive. Authors and poets depicted characters with a lisp as endearing and innocent, associating the speech defect with youthfulness and unspoiled purity.


First Public Release of Lisp

The first public release of Lisp took place in 1958, when McCarthy published a paper titled 'Recursive Functions of Symbolic Expressions and Their Computation by Machine.' This paper introduced Lisp as a formal programming language and presented the concept of a Lisp interpreter, which allowed users to write and run Lisp programs. This marked the beginning of Lisp's widespread adoption and its significance in the field of computer science.


First Lisp Implementation on an IBM Mainframe

In 1962, an initial implementation of Lisp was built on an IBM 704 mainframe computer. This implementation, known as the 'IBM 704 Lisp', was influential in demonstrating the practicality of Lisp and showcasing its unique features like dynamic storage allocation and garbage collection.


Origins of the Term

The term 'lisp' is said to have originated from the sound produced by people with a lisp when attempting to pronounce the letter 's.' The 'th' or 'z' sounds that replace 's' create a slight hissing or slurring effect, resembling the sound 'lisp.' This connection between the spoken sound and the term itself helped establish 'lisp' as the preferred label for this speech impediment.


Lisp Machine Era

During the 1970s and 1980s, Lisp gained popularity with the development of Lisp machines. These specialized computers were designed to optimize the execution of Lisp programs. Symbolic processing and powerful garbage collection techniques made Lisp machines particularly well-suited for artificial intelligence and expert system applications.


Evolution of Lisp Dialects

Throughout the 1960s, different dialects of Lisp emerged as researchers and developers extended and modified the language to suit their specific needs. Popular variants include MacLisp, InterLisp, and the influential dialect called Scheme, which was developed in the 1970s. These dialects introduced new features and improvements to Lisp, contributing to its flexibility and making it suitable for a wide range of applications.


Speech therapy emerges for lisping

In the 1920s, speech therapy emerged as a profession, and addressing lisping became part of its scope. Speech therapists developed techniques to assist individuals with a lisp, using exercises that focused on tongue placement and articulation to correct the speech defect.

20th Century

Speech Therapy and Treatment

During the 20th century, speech therapy programs expanded, addressing various speech disorders, including lisp. Speech therapists developed techniques to help individuals with lisps improve their speech proficiency. Exercises involving tongue placement, airflow control, and sound repetition were employed to correct lisping. The introduction of speech therapy played a crucial role in assisting those with lisps to overcome their speech impediment and gain confidence in their communication skills.

19th Century

Diagnostic Recognition

During the 19th century, medical professionals recognized 'lisp' as a distinct speech disorder. It became a commonly used term in diagnosing and treating individuals who struggled with pronouncing 's' sounds. Early diagnostic tools and exercises were developed to assist those with a lisp in improving their speech.

Modern Times

Diversifying Use of 'Lisp'

In modern times, the term 'lisp' has expanded beyond its initial medical context. It is commonly used to describe a speech impairment, but it has also found its way into pop culture and the realm of programming languages. In computer programming, Lisp is a family of programming languages known for their unique syntax and the use of parentheses. This usage of the term 'lisp' originates from the acronym 'LISt Processing.' Its adoption in computer science has led to further diversification and popularization of the term beyond its original linguistic and medical connotations.


Lisp Machines and Symbolics

Lisp Machines, dedicated computers optimized for running Lisp programs, became commercially available in the early 1980s. Symbolics, a company founded in 1980, played a significant role in the development and promotion of Lisp Machines. These machines offered high-performance computing tailored for Lisp, providing a specialized environment for Lisp programming and aiding its continued popularity in academia and research.

20th Century

Speech Therapy Advances

In the 20th century, significant advancements were made in the field of speech therapy for people with a lisp. Techniques and exercises like the 'S-blend technique' and 'sliding a smile' were introduced to train individuals with lisps to produce correct 's' sounds. Speech therapy played a crucial role in helping individuals overcome this speech impediment.


Lisping portrayed differently in popular culture

In the 1940s, popular culture began to portray lisping in a more negative light. Characters with a lisp were often depicted as comic or villainous, perpetuating stereotypes and making fun of those with the speech defect. This representation had a lasting impact on public perception.


Common Lisp Standardization

In 1984, the development of a standardized version of Lisp called 'Common Lisp' was initiated. Common Lisp aimed to consolidate different dialects of Lisp and provide a unified language specification. The effort resulted in the ANSI Common Lisp standard, which was released in 1994 and played a crucial role in maintaining compatibility and portability across various Lisp implementations.


Public awareness and acceptance grow

In the 1970s, public awareness and acceptance of speech disorders like lisping started to grow. Education campaigns and increased understanding helped reduce stigmatization and encouraged empathy and support for individuals with lisps. Society began to recognize that lisping was not a reflection of intelligence or character.


Lisp's Influence on Programming Paradigms

In the 1990s, Lisp's impact on programming paradigms became evident. The functional programming paradigm, which emphasizes immutability and the use of higher-order functions, drew inspiration from Lisp's functional programming capabilities. Lisp also played a role in the development of object-oriented programming, with languages like CLOS (Common Lisp Object System) providing object-oriented features within a Lisp framework. These contributions showcase Lisp's enduring influence on programming language design and the evolution of modern programming practices.


Lisp Acceptance and Culture

While a lisp was once stigmatized, attitudes towards lisps have shifted over time. Many people with lisps embrace their unique way of speaking and view it as part of their identity. Lisps have become more accepted within society, and there is increased awareness and understanding of speech impairments. Today, people with lisps are appreciated for their individuality and their ability to communicate effectively despite challenges.


Scheme: A Dialect of Lisp

In 1975, Scheme, a minimalist dialect of Lisp, was created by Gerald Jay Sussman and Guy L. Steele Jr. Scheme emphasized simplicity and elegance, offering a small but powerful set of language constructs. Scheme became widely used in academic settings and played a significant role in the development of functional programming and language design.


Lisp as an identity and linguistic phenomenon

In the present day, the term 'lisp' not only refers to the speech defect but has also expanded to become an identity and linguistic phenomenon. Lisp programming language, developed in the late 1950s, adopted its name due to the pronunciation resemblance to the speech defect. Lisp is now widely recognized as one of the oldest and most influential programming languages.


Continued Influence and Modern Usage

Today, Lisp continues to be influential in various fields, especially in the domains of artificial intelligence, robotics, and computer science research. It has inspired and influenced numerous programming languages, including JavaScript, Python, and Ruby. Lisp's unique features, such as homoiconicity (code as data) and macros, have had a lasting impact on the evolution of programming languages and software engineering practices.

Did you know?

Did you know? The famous Greek philosopher, Aristotle, reportedly had a lisp. Some might say he was a 'thmart' guy after all.


awareness fun diversity language speech

First identified

4th May 2015

Most mentioned on

4th May 2016

Total mentions


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