What is Gherkin and why does Cucumber use it?

Gherkin is the Given/When/Then plain-language syntax Cucumber parses into runnable tests. Real value: it forces a conversation between BA/PM/dev before code is written (the "three amigos" workflow). If BAs do not read the features and devs write them alone after the fact, Gherkin adds overhead with no benefit — just use plain test code.