Definition
Used to indicate that the current topic of conversation is about a particular person or thing.
说起，谈起
Talking of the weather, it's absolutely beautiful today.
说到天气，今天真是美极了。
Talking of the new manager, what do you think of him?
说到新经理，你觉得他怎么样？
Talking of vacations, we are planning a trip to Europe this summer.
说到假期，我们计划今年夏天去欧洲旅行。