Today we had two words have one meaning
Weather mean الطقس ، الجو
Ataqs , algaw
Even they start with ال
But in algaw we pronunce ال
But in Ataqs we don't pronunce Al
Because there's rules called ( اللام القمرية ، اللام الشمسية )
اللام الشمسية allam ashamseia
Mean the ل which not pronunce in the word , and how you can know it ?
When latter after ل contain the letters which in box number 1 then then the ل will not pronunce as in Ataqs word
But if the letter after ل contain the letters in box number 2 then you will pronunce the ل as which in elgaw word
Don't worry by memorize much words you will know the word contain لام شمسية or لام قمرية
It's like when you pronunce water by t and pronunce the t as d
Even the different much less this example