It is not a coincidence that the website of Eric Evans, the author of the original DDD book, is located at http://domainlanguage.com. Fundamental concepts of DDD such as ubiquitous language and bounded context are both based on the concept of language. It might sound strange to those who spent not many years developing software because for less experienced developers the only language that is important is a programming language. We learn to program usually by studying some concepts and applying them in practice using one of the programming languages. We think that we can translate a human language to a programming language and this is the essence of our work. There is some degree of truth there indeed. However, this is by far not the most important part of the developer's daily routine.

Two people can understand each other only if they can speak one language. It does not necessarily need to be verbal, it might very well be a finger language or the language of music. But both interlocutors need to share the same understanding of this common language, otherwise, there will be trouble. Not only they need to speak the same language, but this language must be in one context. There is a whole book called American and British English: Divided by a Common Language? by Paul Baker, which describes how different the same language became after being split by the ocean for a long enough time.

In this section, we will look deeper into the importance of language and context in which these concepts are crucial for successful software projects.