The main point of language is to convey information, between humans. This transfer of information could happen by several means. Speech is only one of them. In beginning it was the only means humans knew off. With passage of time humans learned to preserve language in written form. Any information contained in speech i.e., sound waves becomes dead as soon as the speaker utters them; unless this is preserved in writing.
Now coming to your question, why I call the Arabic spoken at the time of prophet as a dead one? Since no one speaks this language, any more? What is the proof? Unfortunately evidence is contrary to claims, from natives of Arabia and many others. If you look around, you find numerous contradictory translations and tafaseers of the message available. This is why. Please contemplate why even so called natives of language, have resort to supposed sayings of prophet written hundreds of years after the noble prophet. What are they telling us? It is their pride that keeps them from admitting that they do not know the language and hence the message. Do you believe message was meant for only prophet and his companions? However, prophet and his companions did take pain to preserve message and its language both in writing. It is this preserved form of language that we need to dig into, to understand the message.
For your query regarding why I use Rubb (thanks for correcting my transliteration mistake) instead of Allah, please read this thread with an open mind.
The model that is unfortunately created in the name of noble prophet of Arabia leads to following fatalism and misconception in Muslim minds.
1. The person was and will be more important, than message and hence creator of message,i.e., Rubb. Please consider, this prophet was noble a person even before prophet hood. Everybody seems witnessing to his virtues character, foes and friends alike. But what changes, was he able to bring in the society. Answer is a resounding “None”. But look at 23 years of older part of his life, with the message a revolution took place. Point to ponder, did prophet as a person or the message enabled the revolution?
2. Furthermore, by taking him as a person responsible for this revolution, aren't we guilty of given him a status bigger than the message and hence the creator of message. If we consider somebody bigger than creator of message, what is that?
3. In addition this model has driven current Muslims to apathy. They want to wait for somebody some one. They continue to wait for a superman to come for their rescue. Rubb has created all of us to be super men and women. Didn't he tell Malika to bow to Adam, a proto of all men he created? Provided we follow his divine commands.
With lots of love and respect,