When I wanted strings in my app to be translated, I included screenshots so that the translator would understand the context. Otherwise it might be impossible to guess what a very small string is supposed to represent.
For a while I was working as a manga translator, and in that case it would have been doubly important to see more context. Actually it probably wouldn't even work to split a translation task for multiple translators, since each might decide to translate something inconsistently. For example speaking style, naming of things etc.
This will probably work best for longer pieces of text like business text where you can easily guess the meaning without seeing any context and where you don't need to make decisions that might affect text that comes a hundred pages later.
This is a very interesting startup, if you want more gyoza distractions I'll be travelling in Tokyo until 3rd of May.
The context problem is a continual issue with translation - but most of the time our customers handle it by adding comments to jobs.
We do allow you to attach comments to the job call - so you can add context there and also links to related material if required. We're considering adding an option to attach files too.
You can also group jobs together if you want them to be handled by a single translator - this obviously takes longer but makes sense for all-in-one projects.