Level Ordering Hypothesis

The Level Ordering Hypothesis is a hypothesis proposed in Siegel (1974) which takes the form in (i):

(i) Class I affixation \/    Word Stress Rules \/    Class II affixation

This hypothesis embodies the claim that affixation takes place in two linearly ordered blocks, which are separated by the word stress rules.

Example
The derivation of the English words productívity and prodúctiveness runs as follows. In the case of productivity, we first put together pro-, duct, -ive, and -ity (all Class I), and then we apply the stress rules (productívity). The derivation of productiveness is crucially different. First we put together pro-, duct, and -ive, then we apply the stress rules (prodúctive), and only then do we have the chance to add the Class II affix -ness, giving prodúctiveness. Since the affixation of -ness takes place after the stress rules have applied, it is correctly predicted that -ness cannot affect the stress already assigned to productive. Allen (1978) has replaced Siegel's Level Ordering Hypothesis by the more detailed Extended Level Ordering Hypothesis.

Link
Utrecht Lexicon of Linguistics