Our documentation set includes some diagrams where text is integral and can't be handled in callouts, like flowcharts and entity relationship diagrams. Our documentation is translated, so these diagrams need to be translated too. But diagram design is informed by the amount of text we need to include -- this box needs to be big enough for that word, this branch in the flowchart needs to be able to hold that four-word question, and so on.
But not all languages are equally verbose. If our diagrams were translated to German, probably many bits of text would overflow their bounding shapes or otherwise not fit well. If the translation were to Hebrew, much of the text would be swimming in vast seas of excess space. And I have no idea what would happen in Japanese (which is actually one of our current target languages, unlike my other examples).
When I'm laying out a fairly complex diagram that uses text, how should I account for the space needs of translation? Are there well-known ratios I should use in planning, for example that language X averages needing 1.5 times the horizontal space of English (so I should just add in some extra space)? Are there things I can do technically (in Visio) to support auto-scaling, so that if all the boxes need to be wider that can be done globally and not by editing each box? Or do technical translators routinely redraw diagrams and I shouldn't worry about it? (I don't have a way to ask ours what they do, so I'm asking what's commonly done.)
In this related question I asked about the mechanics of translating text in diagrams. In this question I'm asking about content, not mechanics.