How can you explain what reduced compliance and high alveolar surface tension means to a layperson?

The key to understanding reduced compliance and high alveolar surface tension is to visualize the more general concept of surface tension. Surface tension is a phenomenon that occurs at the boundary of liquid and air. Liquid particles are more dense than air (i.e. they are packed together more tightly), which causes those particles to push in toward each other. At the liquid-air boundary, the effect is analogous to stretching a thin membrane over the liquid. Think about what a glass of water looks like when you carefully fill it above its rim. A small bump of the liquid extends above the rim, which is maintained due to surface tension at the liquid-air boundary. Another way to look at surface tension is when you see a bug skimming the surface of a pond. The bug is denser than the pond liquid, but surface tension at the top of the pond allows the bug to appear as if it is walking on water.

Surfactants can change surface tension characteristics. If you put a drop of soap into the glass of water, that soap makes the surface more slippery (i.e. it reduces surface tension) and you will not see the bump of liquid above the rim. Likewise, with lower surface tension on a pond, the water-walking bug would sink.

Moving now into how surface tension works in our lungs, our alveolar sacs are coated with a thin layer of surfactant liquid. If surface tension is loo low, the sacs are in a state of reduced compliance and they will collapse into themselves. If surface tension is too high, an impenetrable barrier forms between the air in the sacs and blood in the capillaries around the sacs. In both cases, airflow in the lungs is reduced.

Asthma is an example of high alveolar surface tension. The lungs air sacs in this situation are akin to a glass of water that has plastic stretched across its surface. Nothing will pass through that plastic. Reduced or noncompliant lungs will result from low surface tension. With low surface tension, there is no force to hold the air sacs open (or, to extend an analogy, to support a bug on the surface of the water).