English pronunciation can be difficult. There are many different ways to pronounce the same groups of letters.
In this video I look at an amazing poem ‘The Chaos’ which highlights many example of words which look similar but sound different.
Here is the fourth verse
Ivy, privy, famous; clamour
And enamour rhyme with hammer.
River, rival, tomb, bomb, comb,
Doll and roll and some and home.
Stranger does not rhyme with anger,
Neither does devour with clangour.
Souls but foul, haunt but aunt,
Font, front, wont, want, grand, and grant,
Shoes, goes, does. Now first say finger,
And then singer, ginger, linger,
Real, zeal, mauve, gauze, gouge and gauge,
Marriage, foliage, mirage, and age.
You can find the rest here http://www.i18nguy.com/chaos.html