ES5 is the JavaScript you know and use in the browser today it is what it is and does not require a build step to transform it into something that will run in today's browsers
ES5 is the Javascript version available in the browsers today, To execute ES5 you dont need any build mechanism or transpilers to convert into other formats
ES6 (also called ES2015) is the next iteration of JavaScript, but it does not run in today's browsers. There are quite a few transpilers that will export ES5 for running in browsers. It is still a dynamic (read: untyped) language. ES6 is available in most of the modern browsers
TypeScript provides an optional typing system while pulling in features from future versions of JavaScript (ES6 and ES7).
Note: a lot of the transpilers out there (i.e. babel, TypeScript) will allow you to use features from future versions of JavaScript today and exporting code that will still run in today's browsers.
