Audio with Theyab's pronunciation

When I started learning to read Arabic, I was horrified to discover that most
words are written without some of their letters.

Take for instance, yesterday's word: mashaarii:-kum. In Arabic it is written like
this مشاريعكم but if you literally translated this word into English, letter for letter,
it would look like this: mshaarii:-kum.

So what happened to the missing letters?

Once upon a time, Arabic words were actually written with all their letters,
but the language gradually evolved to include just consonants and long vowels -
aa, ii, uu.

So what happened to the short vowels, a, i, uAnd how can people read their
own language when some of the letters in each word are simply not there? 

As you can perhaps tell, right now I'm far from muriiH. I might need istiraaHah
from learningEven the people closest to me tell me "akhidh-ay raaHt-ich!" 

So raaH artaaH and tell you the secret to understanding written Arabic,
in spite of its missing letters.

If you look at today's word, and then at the table below, you'll notice that
the first four words have something in common; they all contain the letter r
and the letter H. This is called a root. Any words with those same consonants
have a similar meaning.

The root r-H is always related to comfort, resting, relaxation.  A good root 
to know if ever I need to defend my taste for laziness.

مريح muriiH Comfortable
الستراحة al-istiraaHah A break, rest area
اخذي راحتچ akhidh raaHt-ik Relax! (>f)
راح ارتاح raaH artaaH I’m going to relax
صعب Sa:ab Difficult
بس احب bas aHib I just like