Linguistic progress is also hierarchical, in that the upper levels contain the structure of the lower. For example, someone who can speak a fully-fledged vernacular language can also use a jargon, even as an adult does not normally lose the capacity to speak to a small child.

Major tongues tend to show this most clearly. There is a reference standard language, the acrolect, however many actually speak it, and then at the other end of the scale a number of localised dialects with fairly wide variations between themselves, although they are recognisably of the same language. Mesolects are in between. Most can speak a narrow range of registers within the hierarchy, and a very few a wide range stretching from the acrolect to one or more basilects.

During the zenith of the English language fifty or sixty years ago a fairly similar front-of-house acrolect obtained throughout the English-speaking world, and most of the mesolects if not the basilects were mutually-understandable. Some say that this zenith has continued up to the present.

LangX is based on this model, and the guarantee of freedom is vertical open-endedness. Thus, from a very basic lowest common denominator basilect, accessible to everyone in the world, it should be possible to develop towards a rich and totally-comprehensive global language - as in the normal progress from infant to adult speech, and the expression “the child is father to the man”.