Clear, shared concepts and terminology play a crucial role.
Regarding terminology, everybody needs to understand what words mean in the spec. If you are inconsistent with words or use words that the spec's audience will not recognise, then there is a risk of failure.
But that's not all. Even with perfect terminology, you need to have a clear and shared agreement on the concepts underlying the words. If differen stakeholders "cut up" reality in different ways, or, in other words, don't see the same things when they look around, and your spec fails to address this, then you are at risk too.