It is easier to ask the question than to answer it. The best that we can
do is to say that the word is one of the smallest, completely satisfying
bits of isolated "meaning" into which the sentence resolves itself. It
cannot be cut into without a disturbance of meaning, one or the other or
both of the severed parts remaining as a helpless waif on our hands. In
practice this unpretentious criterion does better service than might be
supposed. In such a sentence as _It is unthinkable_, it is simply
impossible to group the elements into any other and smaller "words" than
the three indicated. _Think_ or _thinkable_ might be isolated, but as
neither _un-_ nor _-able_ nor _is-un_ yields a measurable satisfaction,
we are compelled to leave _unthinkable_ as an integral whole, a
miniature bit of art. Added to the "feel" of the word are frequently,
but by no means invariably, certain external phonetic characteristics.
Chief of these is accent. In many, perhaps in most, languages the single
word is marked by a unifying accent, an emphasis on one of the
syllables, to which the rest are subordinated. The particular syllable
that is to be so distinguished is dependent, needless to say, on the
special genius of the language. The importance of accent as a unifying
feature of the word is obvious in such English examples as
_unthinkable_, _characterizing_. The long Paiute word that we have
analyzed is marked as a rigid phonetic unit by several features, chief
of which are the accent on its second syllable (_wii'_-"knife") and the
slurring ("unvoicing," to use the technical phonetic term) of its final
vowel (_-mü_, animate plural). Such features as accent, cadence, and the
treatment of consonants and vowels within the body of a word are often
useful as aids in the external demarcation of the word, but they must by
no means be interpreted, as is sometimes done, as themselves responsible
for its psychological existence. They at best but strengthen a feeling
of unity that is already present on other grounds.