Let them speak their mind. =Let them say what they're thinking honestly. You should give the manager a piece of your mind. =You should scold the manager (because you don't like something that he/she has done). I really crave a fresh perspective. =I really want to get a different point of view. Hope this helps!

Hi Omness, Great question: this type of idiomatic language can be difficult to understand. To let somebody speak their mind means to speak freely. To give somebody a piece of your mind means to tell somebody what you think. To crave a fresh perspective means to look at a problem in a new way, from a different angle. If I can help with anything more, please send me a message!! Liam