For example, the sentence: Every farmer owns a donkey has two interpretations: Depending on which quantifier expression is higher, the meaning is shifted, but because this movement does not occur until LF, the structures are pronounced identically.
Similarly to this account for scopal ambiguity in quantifier raising, Pesetsky proposes that in the structure of unhappier, happy and the comparative suffix -er are the first to combine, since -er may not attach to adjectives that are longer than two syllables.
At LF in the following phase, -er undergoes raising, forcing the interpretation of the word to be "more unhappy" and not "not happier".
[5] She argues that un- adjoins at a late stage of the derivation in LF, possibly after the spell-out of [happy -er].
Thus, the complex structure emerging as a result of head movement to the exclusion of LP allows for the phonological bracketing.