Tongue+twisters

beginners:Three witches watch three swatch watches. Which witch watch which swatch watch? interm:Three switched witches watch three swatch watch switches. Which switched witch watch which swatch watch switch? expert:Three swiss witch-bitches, which wished to be switched swiss witch- bitches,wish to watch three swiss swatch watch switches. Which swiss witch-bitch which wishes to be a switched swiss witch-bitch, whish to watch which swiss swatch watch switch?