Thanks everyone for answering my question on the future tense in Arabic.
After reading the answers I came up with a few more.
(1) Is this categorical statement true: "classical Arabic had only two
tenses and the articles 'sa' and sawfa' had never been used?"
It looks like the meaning of the following quote is the same:
"using the terms "present tense" "future tense" etc. for classical
arabic is misleading. there is the perfect ("past" al-ma:Di: but the
usage is sometimes different) and the imperfect (al-muDa:ri3 ;
usually the imperfect indicative is in question)"
(2) I assume that the particles 'sa' and 'sawfa' are used in modern
*written* Arabic. Are they being used in conversations, in colloquial
everyday Arabic on the street and marketplace?
(3) Is it possible to pinpoint a moment in history, at least approximately
when they first entered usage?
Thanks