[janalsncm]

Communication is a lot more than just competency in a language. It is correlated (especially at the low end of competency) but has a lot more to do with empathy and making an effort. There are plenty of native English speakers I’ve worked with that I would score low on communication ability because they can’t explain themselves unambiguously and I end up having to ask a lot of follow up questions.

As long as it’s not a catastrophic mental disability, having a disability should not preclude someone from communicating clearly. As long as they slow down and actually take time to make themselves clear, it shouldn’t be a problem.