Here, in order to form a new word, one or more of the vowels of the old
word are changed, as in _man--men_, where an _e_ is substituted for _a_;
_ran--run_, where _u_ is substituted for _a_; _lead--led_, where _e_,
with its proper sound, is substituted for _ea_ with its proper sound.
This method is used to a very limited extent in English. When the
history of the words in which it occurs is studied it is discovered
to be but an instance of the wearing out of the different elements of
combined words; but in the Hebrew this method prevails to a very large
extent, and scholars have not yet been able to discover its origin in
combination as they have in English. It may or may not have been an
original grammatic process, but because of its importance in certain
languages it has been found necessary to deal with it as a distinct and
original process.