1.      Most words double the consonant when adding a suffix beginning with a vowel:

2.     Most words with a final  e  keep the  e  when adding a suffix that begins with a consonant:

3.     Most words drop the final  e  when adding a suffix that begins with a vowel:

have + ing  = hav + ing = having

give + ing = giv + ing = giving

4.     Most words change  y  to  i  when adding a suffix not beginning with i:

try + ed = tri + ed = tried

cry + ed = cri + ed = cried

5.     Most nouns form the plural by adding s:

book + s = books

dove + s = doves

6.     Most nouns form the plural by changing y to i when adding es:

story + es = stori + es = stories

country + es = countri + es = countries

7.     Nouns ending with  s,  ss,  sh,  ch, and  x  form the plural by adding  es:

inch + es = inches

class + es = classes

8.     Most nouns form the plural by changing  f  or  fe   to  v  before adding  es:

half + es = halv + es = halves

wife + es = wiv + es = wives