The saying "talk is cheap" means that speaking or making promises is easy and requires little effort, but taking action or fulfilling those promises can be much more challenging and may require significant effort, resources, or commitment. In other words, it's often easier for someone to say they will do something than it is for them to actually follow through and do it.
The phrase is used to emphasize the importance of actions over mere words. It suggests that actions speak louder than words and that someone's true intentions and commitment can be better judged by what they do rather than what they say. It's a reminder that empty promises or grand speeches mean little if they are not backed up by concrete actions.
This saying is often used in situations where someone makes big claims or promises without taking any substantial steps to support their words. It's a way to encourage people to be more accountable for their actions and to be cautious of trusting words alone without any evidence of follow-through.