PHP regex(?) call needed

i have a $string  (max length, say 100 chars) that is (english) text/paragraph that can
contain alpha/numeric/punctuation/linebreaks/hyphens/apostrophe/etc.

i'd like a statement that determines  yes or no   are there  "words" (azAZ09-_')  that exist that are longer than $MaxLength characters  without an intervening  word separator (i.e., non word character).
THe particulars are somewhat flexible for exact definition of "word" and "separator"

is there some sort of regex (or other) PHP call that can evaluate  $String  for  words > $MaxLength

thanks!