G: TL;DR: In Greek, gyro is pronounced roughly "yee-roh" (Γύρος).

Breakdown:

• The Greek word is Γύρος.
• Γ (gamma) before front vowels like υ is pronounced like a soft "y."
• υ sounds like the German "ü" or English "ee."
• The ρ is a rolled or tapped "r."
• The ος ending is like "ohs" but often softened.

So it's "YEE-rohs", but in casual speech, especially when ordering food, “yee-roh” is fine.