The alphabet is split into vowels and consonants.

Here are the vowels:

a  e  i  o  u

Consonants are all of the other letters in the alphabet:

b  c  d  f  g  h  j  k  l  m  n  p  q  r  s  t  v  w  x  y  z

All words need to have at least one vowel.

You can change words into different words by changing their vowels or their consonants.

Look at this word ladder:

The word cat changes to bar by changing a consonant each time you travel down the ladder.