Quote Originally Posted by Sweden2011 View Post
How do you know that there are no inflectional affixes?
As I understand it, inflectional affixes give grammatical information like number, case, tense, aspect, etc, which the ones in your words do not. If I change the verb operate to operates or operated, it is inflection- the same word, but marked for the third person singular or the past tense/past participle (grammatical information). But changing operation to operational is straight derivation- forming a new word, an adjective from a noun.