Audience member asks how to apply DDD when the client is the domain expert but refuses to share or learn the ubiquitous language. Heimeshoff: you end up doing the work yourself — write specifications/tests in what you believe is the domain language, print the test output and give it to them for corrections, offer a DSL of allowed commands/events so they can write specs without programming, and iterate until they agree. Once they see code/product improve and trust you, they usually start collaborating — especially if you can get them into an EventStorming.