The root problem is not misunderstanding but not trusting each other. When the team implementing something says it is two weeks while the other team believes it should be just a day - in a world with full trust the second team would just accept that the first team has more expertise. But why should the teams trust each other? There is always the option that the estimation is not based on the real work required - but just an attempt to get some slack.

With translation you can show that there is a depth of arguments for that or that position - this is improving the trust.