In Bulgarian, "с" and "със" mean "with" and are used based on pronunciation rules.

Written Bulgarian

1. Use "с":
   • Before words starting with a consonant (except "с" or "з").
   • Example: "с приятел" (with a friend).
2. Use "със":
   • Before words starting with "с" or "з".
   • Example: "със злато" (with gold).

Spoken Bulgarian

People might use "със" more often to make speaking easier or to emphasize, even if the next word doesn't start with "с" or "з".

Same rules apply to "в" and "във".

• Written:
  • "в" before words starting with a consonant.
  • Example: "в къщата" (in the house).
  • "във" before words starting with "в" or "ф".
  • Example: "във вратата" (in the door).
• Spoken: "във" might be used more often for smoother speech, even when not necessary.

Key Differences

• Written: Strict rules.
• Spoken: More flexible.