Answer:
The difference is due to the succeeding vowel sound strength (whether it is weak or strong)
Explanation:
"ch" produces "k" like sound. Whenever , alphabet "c" with in any word comes before any weak vowel sound such as i or e , it always sound as "ch".
Therefore, c and ch in gioco and giochi are sound similar.
"sc" sounds like "sh" when it comes before any weak vowel sound (as in the case of capisci)
"sc" sounds like "sk" when it comes before any strong vowel sound (as in the case of capisco)
