Learn Italian: Tuttavia, stava ristampando le lettere per la nuova disposizione. - However, she was reprinting the letters for the new layout.

The prefix ri- is added to verbs to indicate that an action is being repeated, much like the English prefix 're-'. Here, it is attached to the base verb stampare (to print) to form ristampare (to reprint). In this sentence, we see it conjugated in its gerund form (ristampando).

Why use the construction stava ristampando instead of the regular imperfect ristampava?

Both can translate to 'she was reprinting', but the past continuous structure (stare in the imperfect + gerund) strongly emphasizes that the action was right in the middle of happening at a specific interrupted moment. The regular imperfect (ristampava) is a bit broader and can also imply a habitual past action ('she used to reprint').

Is disposizione a false friend in this sentence?

Partially. While it can mean a person's mood or 'disposition', in a physical, spatial, or design context like this one, it translates to 'layout', 'arrangement', or 'placement'. It comes from the verb disporre (to arrange or lay out).

How can we tell if lettere means letters of the alphabet or written mail?

The word lettera can mean both, just like in English! You always have to rely on context. Here, the mention of printing and a nuova disposizione (new layout) makes both interpretations possible, though 'written letters' (documents) being reformatted for a new layout is the most natural reading.