From InDesign CS6 onwards, it is possible to set a text frame to automatically resize itself based on the content of the frame. The direction of this auto-sizing can be specified (e.g. downwards only, both down and to the right, etc.). This functionality can then be used to ensure that text will never go overset in a frame.

Coupled with anchored objects, this functionality can be a powerful tool for ensuring that the design and layout of your document is maintained throughout the translation process.

NOTE:
It is not possible to set a "maximum" size for the frame, so it is possible that the frame will grow over other content, or even off the spread. For this reason, it is still necessary to provide styles that will ensure that localized text will still fit the approximate size of the original text.