How is verification affected when a file type is missing?

When a user doesn't have a file type installed, a warning message appears saying that the following features will be restricted or unavailable:

- Saving
- Verification
- Quick Tags
- Preview

It seems obvious to me how saving, quick tags and preview will be affected in this situation, but what impact will a missing file type have on verification? Are users able to run a verification without a file type installed? What are the limitations, if any?

With the Microsoft Word 2007 - 2013 file type being phased out in Studio 2017 SR1, I'm particularly interested in how users of Studio 2014 and earlier are affected by not having the new MS Word file type available.