Mininal Pairs.

Minimal pairs are kind of same words talking about the sound, not the meaning but this have a little differences in their sounds.

Examples:

Sheep (i:)/ Ship (i)
In the first word the letter "i" sounds larger.
Cat (ae) / Cart (a:)
In "cat" the "a" sounds like an "a" and
Look (u) / Loop (u:)
Darling (a:) / Dialling (ai)
Tail (ei) /  Toil (oi)
Coat (eu) / Coot (u:)
Rot(r) / Lot (l)
Pull (p) / Bull (b)
Heart (h) / Art (-)
Worse (w) / Verse (v)