 Let's analyze the word unacceptable. Clearly, the base form is accept and it is a verb. Since unaccept doesn't exist, we have to attach the adjectival suffix obel, which turns the verb into an adjective first. Now we have two choices. Either we attach the prefix un and get unacceptable, or we attach the suffix itty to generate acceptability. Let's show option one first and attach the prefix un, which, like many other present-day English prefixes, can precede many elements, verbs such as undo, or adjectives like unhappy and even nouns, as we will see in a second. So it has no inherent word class and we label it with a question mark. The new word class is thus the old one. Unacceptable is still an adjective. To this adjective, we can attach the nominal affix itty, turning the whole word into a noun. Let's now look at the second option. This option first generates the noun acceptability and then attaches the prefix un to this new nominal stem. The morphological processes involved can easily be described. Accept is the base form. All other processes are examples of derivation. And the morphological operations? Well, in all three cases, we have an operation of affixation, where the attachment of itty involves a stress shift, a phonological change, and a special orthographical variant of abl. Here are both solutions side by side.