Question
  Salaam,
  
  1. I just want to confirm that tajweed was the spoken language of the prophet
  and the Arabic speaking world at that time when the Qur'an was revealed to
  guide mankind? 
  
  2. Classical Arabic is the equivalent to tajweed and that tajweed is not a
  later innovation to how the Qur'an was revealed, recited and understood?
  
  3. Lastly, when the companions addressed the prophet by his first name they pronounced
  his name as Muhammadun and not Muhammad?  Allahu Akbar is properly
  pronounced Allahu Akbaru? 
  
  4. Is classical Arabic the spoken language at that time.  Your answers
  will be a great help in my studies.
  
  
  
  Answer
  Wa
  alaikum assalaam wa rahmatu Allahi wa barakatuh.
  
  
  1. 
  The natural Arabic that the Prophet, 
   , the Companions, even the
  polytheists, spoke used the same basic rules that we now learn as
  “tajweed” to a far extent. The Arabs spoke with a qalqalah on the
, the Companions, even the
  polytheists, spoke used the same basic rules that we now learn as
  “tajweed” to a far extent. The Arabs spoke with a qalqalah on the 
   letters
  when they were saakinah, they made idghaam of the
 letters
  when they were saakinah, they made idghaam of the 
   saakinah
  when followed by one of the letters of the group of
 saakinah
  when followed by one of the letters of the group of
   , they made tafkheem of the
  letters of the letters in the group
, they made tafkheem of the
  letters of the letters in the group 
   , etc. 
  What they did not necessarily do in speech was lengthen a medd letter
  for 4, 5, or 6 counts. The revelation had these elongations, and was passed
  down from the Prophet,
, etc. 
  What they did not necessarily do in speech was lengthen a medd letter
  for 4, 5, or 6 counts. The revelation had these elongations, and was passed
  down from the Prophet, 
   , to the companions, on to
  us, with these elongations.
, to the companions, on to
  us, with these elongations. 
  
  
  
  2. 
  Classical Arabic is more than just tajweed, but what is now known as
  “tajweed” is part of Classical Arabic. 
  Classical Arabic involves grammar, vocabulary, and how letters are
  pronounced (this last part being tajweed). 
  
  
  
3. 
  The name Muhammed 
   is
  a proper name that can take a tanween.  Not
  all proper Arabic names take a tanween, for example, the name Ahmed does not.
  Some names do not take even a dhammah, such as:
  is
  a proper name that can take a tanween.  Not
  all proper Arabic names take a tanween, for example, the name Ahmed does not.
  Some names do not take even a dhammah, such as: 
  
   and
 and
  
   .
 .
  In Classical Arabic, when you are addressing someone, or calling them, the
  calling 
   is either used
  directly, or implied.  The proper
  name after the ya’ of calling becomes marfoo’ in grammar, and usually (but
  not always) acquires a dhammah.   If
  an Arab in that time wanted to call the Prophet’s attention, they would have
  said
is either used
  directly, or implied.  The proper
  name after the ya’ of calling becomes marfoo’ in grammar, and usually (but
  not always) acquires a dhammah.   If
  an Arab in that time wanted to call the Prophet’s attention, they would have
  said 
   (yaa Muhammedu), but the Muslims
  addressed him by
  (yaa Muhammedu), but the Muslims
  addressed him by 
   (yaa
  Rasoolu-llah).  Notice, the
  proper name after the
(yaa
  Rasoolu-llah).  Notice, the
  proper name after the 
   of
  calling doesn’t acquire a tanween.
  The same name though can take a fat-h or a kasrah,
  as well as the dhammah depending on its
  grammatical place in the sentence.  We,
  in the present day, refer to Prophet Muhammed,
 of
  calling doesn’t acquire a tanween.
  The same name though can take a fat-h or a kasrah,
  as well as the dhammah depending on its
  grammatical place in the sentence.  We,
  in the present day, refer to Prophet Muhammed, 
   , with the tanween dhammah
  when it is grammatically correct.  There
  are times when the fat-h and kasrah are the appropriate endings, and sometimes
  a tanween is appropriate and sometimes not. 
  We don’t know how much grammar you know, but we just want to make
  clear that grammar is the key to which vowel is on the end of the name.
, with the tanween dhammah
  when it is grammatically correct.  There
  are times when the fat-h and kasrah are the appropriate endings, and sometimes
  a tanween is appropriate and sometimes not. 
  We don’t know how much grammar you know, but we just want to make
  clear that grammar is the key to which vowel is on the end of the name.
  Secondly, the Arabic language has a specific rule that they only start a
  phrase or sentence with a vowel, and only end a phrase or sentence with a
  sukoon (the absence of a vowel).  If,
  one is making the proclamation: “
   ”
  (Allahu Akbaru), then the
  dhammah on the ra’ would be dropped in pronunciation, because that is the end of the phrase. 
  If however, the phrase was continued, as in: "
”
  (Allahu Akbaru), then the
  dhammah on the ra’ would be dropped in pronunciation, because that is the end of the phrase. 
  If however, the phrase was continued, as in: "
   ,"
  (Allahu Akbaru Kabeeraa), then the dhammah on the end of Akbar(u) would be used.
,"
  (Allahu Akbaru Kabeeraa), then the dhammah on the end of Akbar(u) would be used. 
  
  
  
  
4. 
  Classical Arabic is what will bring you closest to the Arabic spoken at the
  time of the Prophet, 
   . 
  The grammar is the same, and that is one of the most important parts of
  Arabic to study, the vocabulary is not always the same in present day
  Classical Arabic as it was in the time of the Prophet,
. 
  The grammar is the same, and that is one of the most important parts of
  Arabic to study, the vocabulary is not always the same in present day
  Classical Arabic as it was in the time of the Prophet, 
   , but studying old works
  written by famous scholars of old, will pretty much take you to the Arabic of
  the time of our beloved Prophet Muhammed,
, but studying old works
  written by famous scholars of old, will pretty much take you to the Arabic of
  the time of our beloved Prophet Muhammed, 
   .
.