Simple and progressive forms
I am starting to be confused by the problem of
"you write letters" vs "you are writing letters"
Does Spanish provide for a separate form for this in some way (or is there another reason why the progressive form is a bad translation of the Spanish present tense)?
There is a progressive form in Spanish -- it is estar plus the present participle. Thus, estoy escribiendo-- which means I am writing or estas escribiendo you are writing, etc. It means that you are literally performing the action at the time. Estoy escribiendo esta respusta ahora por exemplo.
As KikiJ notes, the progressive form exists, but in my (albeit limited) experience it's not used as much as we English speakers use our ~ing forms: it's much more common in Spanish to use the present form for the progressive. In other words, I agree with your implied question, Firionel: I don't think that the progressive form is a bad translation of the present tense.