Ease of use means many things to many people, but to me, it's a way of thinking. You must always be religiously thinking about your users and their semantic knowledge of the product or area of interest. Adding more bells and whistles is often not the best for the customer. Making things simpler is usually more successful and more important. It's difficult for development, marketing, and user experience people to have this battle. How to measure the ease of use. Does it matter for sales immediately? Many times products are compared to other products and checklists are created and marketing wants more checkmarks.
So user interface designers and now ‘new’ language interface designers need to be careful and how they assemble the collection of features in order to keep it simple for the customer. It's a religion and must always go back to the development, marketing, and design groups to preach. Developers are notorious for assuming everybody knows everything as they do, especially when they are neck-deep into developing the product. Sometimes developers like to think more complex, clever, means better, more powerful.
Even when two people talk to one another in life, they have to be careful to know the other person's perspective. They want to ensure they are communicating and not wasting their time. So they usually frame the discussion understanding the other person's context of understanding. We all are not perfect and sometimes communicating topics is too complex. We all likewise know people who WANT to talk “above” others to appear more knowledgeable or who are just unaware of the people's perspective.
User interfaces that don’t use spoken language are rigid and incapable of adapting to the person they are interacting with. That is how almost all interfaces have been created up until recently. Designers and developers generalize the user interface and debate ‘how much’ a person needs to know or learn to use a particular product. They then abstract the interface into controls on the screen as best they are able.
Natural language processing will change focus, access to features and functionality in a product. Language can adapt and simplify the user's interactions. To be successful we will still need to go extra mile in order to make sure that the language matches the customer. Language has its own set of challenges, and we need to be robust and human about it. If we do, it will be a radical step forward for peoples interaction with computers.
It's a religion.