Unicode in Five Levels

Just like how a translator at the United Nations listens to a speaker in one language and translates it into another, Unicode acts as a “translator” for computers.

When you press a key on your keyboard, your computer doesn’t see a letter or a number. Instead, it sees a code. Different computers and different programs may use different codes for the same character. That’s where things can get messy—imagine if two translators at the United Nations used different words for the same concept. There would be a lot of confusion, right?

So, Unicode is a universal set of codes that everyone agreed to use. When you press “A” on your keyboard, Unicode tells your computer that’s a U+0041 (that’s Unicode for “A”). This way, no matter what computer or program you’re using, if it’s using Unicode, “A” will always be U+0041, just like how “hello” is always “bonjour” in French, no matter who’s translating.

So yes, just like a translator makes sure everyone at the UN understands each other, Unicode makes sure every computer understands every other computer. It’s the ultimate translator for the digital world!

Explanation using Ladder of Abstraction

The Ladder of Abstraction is a tool for thinking about the details or generalality of an idea. It allows us to move up to higher, more abstract concepts, or down to lower, more concrete details. Let’s apply it to Unicode.

  1. At the bottom of the ladder, we have the binary code that computers use to represent information. For instance, the letter “A” might be represented as 01000001 in binary.

  2. Moving up a step, we can say that computers use numeric codes to represent characters. So, the number 65 represents “A”.

  3. A bit higher up the ladder, we can talk about different character encoding schemes, like ASCII, that computers use. ASCII is a standard that matches numbers with characters, so in ASCII, 65 corresponds to “A”.

  4. Going up another step, we can say that there are many different character encoding schemes, not just ASCII. Some computers and programs use ASCII, others use Latin-1, and others use UTF-8.

  5. At the top of the ladder, we have Unicode. Unicode is a standard that aims to provide a unique numeric identifier for every character, no matter what the platform, program, or language is. It’s a way to unify all the different character encoding schemes.

So, starting from the bottom, we’ve climbed from the concrete representation of “A” as binary, up through numeric codes and character encoding schemes, to the abstract concept of Unicode, a system that encompasses all characters in all languages for all computers and programs. That’s how we can describe Unicode on the Ladder of Abstraction!

Explanation at Five Levels

Let’s look at the concept of Unicode from different comprehension levels.

  1. Child: Imagine you have a big toy box full of different toys, each with a special tag. When you want a specific toy, you look for its tag. Unicode is like a big box for all the characters, like letters, numbers, and even emojis, used in computers around the world. Each character has its own tag so that computers can find and display it correctly.

  2. Teen: You know how we use emojis, letters, and symbols in our texts and social media? There’s a lot more where those came from, like symbols for different languages such as Chinese, Arabic, and many others. Unicode is like a universal codebook that assigns a unique number to every character no matter what the platform, program, or language is.

  3. College Student: Unicode is a standardized system used in computing to represent text. It assigns a unique numeric identifier to each character, symbol, or emoji, allowing consistent encoding, representation, and handling of text expressed in most of the world’s writing systems. This international standard helps ensure that text appears the same across different devices and software.

  4. Grad Student: Unicode is an industry standard designed to facilitate the consistent representation and manipulation of text expressed in any writing system. By uniquely identifying each character, Unicode enables cross-platform text interchange and ensures global interoperability. Understanding Unicode is important when dealing with natural language processing, database design, internationalization, and other language-dependent tasks in computing.

  5. Professional: Unicode is an integral part of modern computing systems, providing a standardized mechanism for encoding characters and symbols from virtually all written languages. It offers broad character coverage, compatibility with existing character sets, and additional properties for characters—essential for text processing. Professionals need to understand Unicode for many aspects of software development, from designing cross-platform applications and websites to managing databases, especially when dealing with internationalization and localization efforts. Unicode’s potential complexities, like different encoding forms (UTF-8, UTF-16), combining characters, and handling of surrogate pairs, are key considerations in these tasks.

Richard Feynman Explanation

Suppose you’re trying to communicate with someone in another country who speaks a different language. You could write a letter in your own language, but the person receiving it may not understand it. Instead, what if there was a universal language that everyone agreed to use for communication? That way, you could write your letter in this universal language, and the receiver would translate it back into their own language when they receive it. This would ensure that everyone, no matter what language they spoke, could communicate effectively with each other.

This is the basic idea behind Unicode. In the realm of computers and the internet, there are many different types of characters that need to be represented - not just the Latin alphabet that English uses, but also other alphabets, symbols, emojis, and more.

In the past, different computer systems used different codes to represent these characters, which often led to confusion and miscommunication. Just like our hypothetical scenario of people trying to communicate in different languages without a universal one.

Unicode is like a universal language for characters. It assigns a unique number - a ‘code point’ - to each character, no matter what the platform, no matter what the program, no matter what the language. When you type a character on your keyboard, the computer doesn’t see the character itself, but the Unicode code point for that character.

This universal system allows for clear, unambiguous communication between different computer systems, making it possible to use almost any character from almost any written language on your computer or on the internet.

Just like the universal language in our imaginary scenario helped people from different countries communicate effectively, Unicode helps different computer systems ‘communicate’ effectively by standardizing the representation of characters.

That’s Unicode for you, in a style Richard Feynman might appreciate. Remember, it’s all about creating a system that everyone can understand and use, regardless of their ’language’ or, in this case, their computer system.

Robin Williams Explanation

Alright, so you’re sitting there thinking, “What the heck is this Unicode thing?” Let me paint you a picture!

Imagine a massive, world-wide party - we’re talking everyone on the planet here. But we’ve got a problem: not everyone speaks the same language. Some folks speak English, others speak Spanish, Russian, Chinese, the list goes on and on! It’s a tower of Babel out there, a real language fiesta!

Now, imagine if you had a magic translator, a little earpiece that could instantly translate every language into one that you understand, and vice versa. Wouldn’t that be awesome? Suddenly, you could communicate with anyone at the party, no matter what language they spoke!

Well, welcome to the world of Unicode! It’s like that magic translator, but for computers! You see, computers speak in numbers, not letters or characters. And different languages have different sets of characters, right? So, Unicode is this universal code that assigns each character from every language its own unique number. So, an ‘A’ in English, a ‘Я’ in Russian, a ‘中’ in Chinese, they all have their own special Unicode number.

And just like that, thanks to Unicode, your computer can communicate with any other computer in the world, no matter what language it’s using. It’s the ultimate party trick for the digital age!

So, next time you’re typing an emoji, remember this – it’s just Unicode’s way of saying, “Party on, world!”


Unicode solves several crucial problems in computing related to the representation, processing, and interoperability of text data. Here are some key issues that Unicode addresses:

  1. Standardization Across Languages: Before Unicode, different character encoding schemes were used to represent the characters of different languages. This meant that a document or text created in one language might not be readable if opened on a system using a different encoding scheme. Unicode provides a single standard that covers virtually all of the world’s writing systems, ensuring that text data is portable and interoperable across different languages and systems.

  2. Consistency Across Platforms and Software: Unicode allows text to be consistently represented and handled across different hardware platforms, operating systems, and software applications. This means, for instance, that a Unicode-encoded document can be created on a Windows system, edited on a Mac, and viewed on a Linux system, all without losing or corrupting the text data.

  3. Comprehensive Character Set: Unicode includes not only the alphabets of languages like English, Spanish, Russian, Arabic, Chinese, and so on, but also a wide range of symbols, punctuation marks, mathematical symbols, and even emojis. This extensive character set supports a wide range of applications, from word processing and desktop publishing to database management and software development.

  4. Support for Modern and Historic Scripts: Unicode supports not only the scripts of modern languages but also many historic scripts. This makes Unicode invaluable for academic, cultural, and linguistic research and preservation.

  5. Ability to Add New Characters: The Unicode standard includes a mechanism for adding new characters and scripts, ensuring that it can continue to accommodate the world’s languages and symbols, including new emojis, as they evolve.

In summary, Unicode provides a universal standard for encoding, representing, and handling text, making it an essential part of the infrastructure of the global digital information ecosystem.

Let’s explain the problems that Unicode solves with examples that a 5-year-old child might relate to:

  1. Standardization Across Languages: Imagine you have friends from all around the world, and they all speak different languages. If you send each friend a drawing, they would all understand it no matter what language they speak, right? That’s because drawings are a universal way to communicate, just like Unicode. It’s a system that computers use to understand all different languages in the same way.

  2. Consistency Across Platforms and Software: Think about your favorite game that you can play on your mom’s phone, your tablet, or even on your friend’s computer. You don’t have to learn how to play the game differently on each device; it’s always the same. Unicode is like that, but for text. It makes sure that text looks the same no matter where you read it.

  3. Comprehensive Character Set: You know how you can use all sorts of different building blocks to build a castle or a spaceship or anything you can imagine? Unicode is like those building blocks, but for writing. It has all sorts of different “blocks” for every letter, number, symbol, or even emoji you can think of.

  4. Support for Modern and Historic Scripts: Remember when we visited the museum, and we saw writings from a long time ago that looked different from how we write today? Unicode is a system that lets computers understand those old writings too, just like it understands the way we write today.

  5. Ability to Add New Characters: You know how you sometimes create new words or secret codes when you’re playing with your friends? Unicode can do that too! If people come up with a new symbol, like a new emoji, we can add that to Unicode so everyone’s computers can understand it.

Let’s illustrate each of these points with some example text or code:

  1. Standardization Across Languages: Unicode allows text from any language to be represented and understood consistently by computers. Here’s an example:

    Text in English: "Hello, world!"

    Text in Japanese (using Unicode): "こんにちは、世界!"

    Both of these phrases can be represented, stored, and processed by computers using the same Unicode standard.

  2. Consistency Across Platforms and Software: Unicode ensures that text can be transferred and displayed correctly across different platforms and software.

    If you write a JavaScript comment in a code file on a Windows machine: // "こんにちは、世界!"

    And then open that file on a Mac or a Linux machine, the comment will still display correctly thanks to Unicode.

  3. Comprehensive Character Set: Unicode includes a huge range of characters, allowing you to represent almost any text or symbol you could need:

    English alphabet: "abcdefghijklmnopqrstuvwxyz"

    Greek alphabet: "αβγδεζηθικλμνξοπρςτυφχψω"

    Emojis: "😃🌍🐱‍👤"

    All of these characters are part of the Unicode standard.

  4. Support for Modern and Historic Scripts: Unicode supports both modern and historical scripts. For example, we can represent text in Modern English and Ancient Greek using Unicode:

    Modern English: "Hello, world!"

    Ancient Greek: "Χαίρε, κόσμε!"

  5. Ability to Add New Characters: As new characters and symbols are invented, they can be added to the Unicode standard. For instance, when a new emoji is created, it can be added to Unicode and then used in text or code:

    New emoji example: "🥳"

    This emoji wasn’t always part of Unicode, but it was added in a later version. Now it can be used just like any other character.

Unicode and ASCII

ASCII (American Standard Code for Information Interchange) and Unicode are both character encoding standards that are used to represent text in computers and other devices that use text. They’re essentially a way to translate human-readable characters into a format that computers can easily process.

ASCII is older, dating back to the 1960s. It uses 7 bits to represent each character, meaning it can define up to 128 characters (2^7). These characters include the English alphabet (in upper and lower case), digits, and common punctuation marks. However, ASCII isn’t sufficient to represent characters from languages other than English or special symbols.

Unicode was developed to solve this problem. It’s a much larger set that can accommodate characters from many different languages, including those that use non-Latin scripts, as well as a wide range of symbols. Unicode uses variable bit encoding, with options for 8, 16, or 32 bits. This means it can represent a significantly larger number of characters (over a million with the 32-bit version).

So, in essence, Unicode is a superset of ASCII. The first 128 characters of Unicode correspond exactly to the ASCII set, which ensures compatibility between the two.

However, it’s important to note that Unicode is just a set of points that map to characters; it doesn’t define how these points are stored in memory. That’s where UTF-8, UTF-16, etc., come in. These are specific ways to store Unicode characters in memory, with UTF-8 being the most common and also being backward compatible with ASCII.