Intelligibility is a non-count noun, so there is no plural form.Another example of a non-count noun is understandable. Because you can not count understandable it will never appear in a plural form (understandables).
The noun form of the adjective obedient is obedience.
The noun form of "acrimonious" is "acrimoniousness."
The noun form for the adjective 'easy' is easiness.The word 'easy' is the adjective form of the noun ease.
The noun form of the adjective noisy is noisiness.The word 'noisy' is the adjective form of the noun noise.
The noun form for the verb to appear is appearance.
The word appear is a verb not a noun. The abstract noun form is appearance.
There is two of them. The answer is (re)appear and (dis)appear.
There is no noun form ending in -ion. Advocate is a noun -- He is an advocate for higher taxes advocacy is a noun -- The are renowned for their advocacy of human rights.
Intelligibility is a non-count noun, so there is no plural form.Another example of a non-count noun is understandable. Because you can not count understandable it will never appear in a plural form (understandables).
The abstract noun forms for the verb to appear are appearance and the gerund, appearing.
Who comes up with these questions? Victory is a noun.
The noun form for the adjective horrible is horribleness.
The noun form of the adjective obedient is obedience.
The noun form of the adjective 'prosperous' is prosperousness.A related noun form is prosperity.
The noun form of "punish" is "punishment."
The noun form of "religious" is "religion."