The Hierarchical Structure of Words
1. Morphemes within words
 morphemes in words have a strict and systematic linear order
consider the morphological structure of fiendishness under this definition:
fiend + -ish + -ness
 within words, morphemes are also organized in highly patterned ways
words have an obvious linear order, but they also have a layered structure
fiend + -ish  fiendish + -ness  fiendishness
( ( (fiend) + -ish) + -ness)
2. Representing the hierarchical structure of words
 in order to provide a more complete representation of the structure of a word,
we need to take into account the following:
 the fact that every simple word contains one root
 the meanings of the derivational affixes in the word
 the fact that each lexical item represents a particular part of speech
 we can convey this additional, necessary information by labeling the
parentheses around each and every constituent
(( (( fiend)Root + ( -ish )DA)Adjective + ( -ness )DA) Noun
 this additional structure is a consequence, as we saw above, of the recursive
application of derivational rules with the result that lexical items may be
embedded in other lexical items.
 the internal structure of words is not a one-dimensional string of morphemes but
a two dimensional hierarchy of related constituents
 nested parentheses are one way of representing hierarchical structures of this
sort, but they have the disadvantage of looking linear
 an alternative representation which makes the hierarchy more apparent is a
branching tree
fiendishness
fiendish
fiend
-ness
-ish
 the appropriate representation for the morphological structure of words is
a labeled branching tree
fiendishnessnoun
fiendishadjective
fiendroot
-ish DA
-ness DA