11 Conjunctions are decomposed into purely right-branching structures using nonterminals appended with a "-LIST" suffix: This right-branching decomposition of conjoined lists is motivated by the general preference in English toward right branching structure, and the distinction of right children as "-LIST" categories is motivated by the asymmetry of conjunctions such as and and or generally occurring only between constituents at the end of a list, not at the beginning.
(in decomposing coffee, tea or milk, the words tea or milk form an NP-LIST constituent, whereas the words coffee, tea do not.)