Some expect that the idea will be presented to them in the form of large blocks visible from a bird’s eye view, that the general mechanics will be shown, and that the details will be added by themselves. Others want the opposite – the minute details from which they will build a high-resolution complete picture.
Some would like information to be presented in a suggestive, imaginative way – with colorful comparisons and allegories. For others, it will be incomprehensible gibberish leading to frustration and a negative assessment of an entire report.
So what does “speak in plain language” mean? As you can see, it means something different to everyone.