In rasam uthmani, some of the ayahs begin letter (huroof)with no vocal sign, as in surah yaasin ayah #21...

Question
Assalamualaikum
In rasam uthmani, some of the ayahs begin letter (huroof)with no vocal sign, as in surah yaasin ayah #21, #64, surah al a'raf ayah #55 and in many other surahs.  How to read those ayahs. Thank you.

Answer
There is a rule in the Arabic language that we can only begin with a voweled letter, never a non-voweled letters (sukoon). When a word then has its first letter with no vowel, a hamzah al-wasl or connecting hamzah, is placed in front of the word. The vowel we use to start the word (not when joining it with that which precedes it) is determined by some rules and depends on whether it is a verb, a noun, or a participle. There is a section of the site which explains the rules of hamzah al-wasl. http://www.abouttajweed.com/hamzah-al-wasl/index.php
Hamzah Al-Wasl is different than hamzah al-qata' in that the vowel we use is not written on hamzah al-wasl, and hamzah al-wasl is only found at the beginning of words whereas hamzah al-qata' can be found at the beginning of a word, in the middle, and at the end. Hamzah al-qata' takes different shapes in that it can be written on a ya', on an alif, on a wow, or on nothing. Hamzah al-wasl is only written on an alif with a small Sad over it. Hamzah al-qata' looks like the head of the letter 'ayn.

We compiled the words in the Qur'an beginning with hamzah al-wasl after stop marks in the Medinah Complex printing of the Qur'an and the vowel used to start them. The list can be found in PDF file in the following link:
http://www.abouttajweed.com/Verbs%20and%20Nouns%20beginning%20with%20hamzah%20al.pdf
You are welcome