Treat the English string like an API. Use pseudocode for logic. Instead of "Files copied: 5" , use {filesCount, plural, one {File copied} other {Files copied}} .

But what happens when that source file becomes blurred ?

A string simply reads: "Save" . Is this a button to save a document? A dialog asking if the user wants to save their progress before quitting? Or a status indicator that the system is saving? Without context, the translator must guess. In German, the translation for "Save" as a command ( Speichern ) versus a noun ( Rettung ) are radically different. The blur is dangerous.

Sharpen your source strings. Add context. Use plural rules. Your translators—and your international users—will thank you. Because in the end, a product is only as clear as its blurriest source file.