Writing Features - Gherkin Language
Behat is a tool to test the behavior of your application, described in special language called Gherkin. Gherkin is a Business Readable, Domain Specific Language created especially for behavior descriptions. It gives you the ability to remove logic details from behavior tests.
Gherkin serves two purposes: serving as your project's documentation and automated tests. Behat also has a bonus feature: it talks back to you using real, human language telling you what code you should write.
If you're still new to Behat, jump into the /quick_intro first, then return here to learn more about Gherkin.