Team work involves commenting on particular keys. Once you leave a comment to the key, it is automatically e-mailed to people, who have the same contribution rights on languages as you, for example if you are contributing to German only and have English as the reference, only team members and owners who are also contributing to German will get your e-mail.
There is an option to reply to someone, who has posted a comment earlier, thus limiting the notification e-mail only to a person you are replying to.
All the comments to keys, as well as anything you would like to discuss can be sent to the project chat (click icon on the right side of browser window).
Optionally, you can configure how you want to be notified – either per channel or globally.