doubling of the short vowel sign in arabic?

Would you like to show in detail the explanation they wrote in the site about your question?

Doubling the short vowels sign is called "shaddeh" in Arabic. But It could be you are talking about doubling the **fatha**, **dammeh** or **kasra signs**at the end of the words, then it would be added when you have an indefinite article to be used with the word, like **a**table, a**person**, **a** man.

They write the indefinite article by doubling that sign at the end of the word.

what you call short vowels are not part of the spelling , they are only for pronunciation and they don't count as vowels

what you say is called "tanween" or nunnation in english. You use it only on nouns,nouns without the definite article "AL".

SO you may say hatha waladon ameeenon (this is an honest boy)..but you can't say hatha alwladon because it has the definite "al"

you can't also use it when the noun is defined by what follows it (mudaf and mudaf Elayh), like hatha daftaro al benti(this is the girl's notbook)

you can say akalto ta3aman tayyeban but you can't use tanween if you say akalto al ta3ama al latheetha..

hope I cleared it enough..I found you this video..hope it helps!!

http://www.youtube.com/watch?v=a138i6ZtgvE