Answer:
The sound of the consonant c is a good example of this. 
Step-by-step explanation:
The letter c is not always pronounced the same in Spanish. When it is followed by the vowels a, o or u, the letter c has the same sound as the letter k. 
A few words with this hard c sound are: 
- la cama 
 - el coro 
 - la cucaracha
 
When it is followed by the vowels e or i, it has the same sound as the s or th in Spain and Equatorial Guinea. 
Some words with the soft sound are: 
- la ceniza 
 - el centro 
 - la cinta