It's known that if the letter before the pronoun ha carries a harakaat, then the ha will have a short sound and vice versa. What..

Assalamu'alaykum,

It's known that if the letter before the pronoun ha carries a harakaat, then the ha will have a short sound and vice versa. What is the significance of this change?

If that rule is to be applied, if I wish to speak the proper Arabic, should I say, "Qara'tu kitaabahoo" instead of "Qara'tu kitaabahu" (with short dhommah) or it doesn't make any difference?

Jazakumullahu khaira

Answer

Wa alaikum assalaam wa rahmatullahi wa barakatuh,

When , is preceded by a letter with a vowel and followed by a letter with a vowel, there is a lengthening of .  If the letter following it is not a hamzah, then the lengthening is two vowel counts, following the natural medd lengthening. This is called .   If under these same circumstances, the letter following the is a voweled hamzah, then it is lengthened the same number of vowel counts that is lengthened.  This lengthening is called . 

Please see the following links for further explanation and examples, as well as a few exceptions to the rule:

http://www.abouttajweed.com/al-mudood_part_3.htm

http://www.abouttajweed.com/al-mudood_part_6_medd_waajib_jaa'iz.htm (lower part of page).

 Wa iyyaakum.

Wa assalaam alaikum