It sounds like your friend also turned on VoiceOver, which speaks items on the screen as you touch them (and sounds like the Siri voice). You will need to go to Settings>General>Accessibility>VoiceOver and turn it off. However, with VoiceOver on the way you use the iPhone screen changes. First, to scroll you will need to flick the screen with three fingers. Next, to activate something on the screen you will need to first tap it once to select it, then double-tap it to activate it. Example: to open Settings, tap Settings once (the voice will say "settings"), then double-tap it again and it will open. The specific steps are:
- Enter you lock code by tapping the first number once to select it, then double-tap it to enter it. Repeat for the other numbers.
- Press Home.
- Tap Settings. Then double-tap Settings.
- Tap General. Then double-tap General.
- Use three fingers on the screen to scroll to Accessibility.
- Tap Accessibility. Then double-tap Accessibility.
- Tap VoiceOver. Then double-tap VoiceOver.
- Tap "On" next to VoiceOver. Then double-tap "On" to turn it off.
To fix the inverted colors, go to Settings>General>Accessibility and turn White on Black to Off.