I'm trying to learn how to read Arabic and I noticed that sometimes the letter Laam (ل) is either silent or takes the pronunciation of the following letter, as in this text from Wikipedia:

As-salāmu ʿalaykum (Arabic: السَّلَامُ عَلَيْكُمْ‎ [asːaˈlaːmu ʕaˈlajkum]) is a greeting in Arabic that means "peace be upon you".

To me it looks like "al-salamu ..." and not "as-salamu ...".

What is the general rule here?

Update: This question is similar to another question about "sun and moon letters". The body of that question answers this one, and builds upon it by asking the reason for the convention.

There seems to be little interest in reopening this question (which has already been answered to my satisfaction). I just wanted to reference my Meta Stack Exchange question that references this one and collects other examples of what I might consider "false duplicate" pairs: When are questions which build upon each other considered duplicates?

  • 2
    I hope I clarified the difference between this question and the other. I would not / did not find the other question, with "sun and moon letters" in the title, by searching for "laam". I don't think that my question would be found redundant by users who do not already know what "sun and moon letters" are. That's the answer, not the question. Commented Jun 22, 2018 at 6:48
  • I think your question would be a better fit for languagelearning.stackexchange.com. I can migrate it for you if you prefer.
    – prash
    Commented Jun 23, 2018 at 22:35
  • I don't mind having the question migrated, or closed for some other reason, as long as people can Google it. I do mind that people don't seem to understand the meaning of a duplicate question here. I might as well ask a question like "why are coronal consonants assimilated in some languages" and mark the "sun and moon letters" question as a duplicate of that one. They build on each other, they are not duplicates. Commented Jun 25, 2018 at 2:24
  • Don't get me wrong, I think this is a great SE website and it's been very helpful to me. Commented Jun 25, 2018 at 3:10

2 Answers 2


The /l/ of the definite article /al/ assimilates with the next consonant when that consonant is coronal. The affected consonants are /t θ d ð r z s ʃ sˤ dˤ tˤ ðˤ l n/ (the letter jim /dʒ/ is not included, because it was pronounced as /gʲ/ in Classical Arabic). They are called sun letters and the others are moon letters.

  • Although, in contemporary dialects, jim at least in the ʒ instantiation can be part of the trigger class.
    – user6726
    Commented Jun 21, 2018 at 19:04

According to Wikipedia, s is a "sun letter", and the "l" in the prefix "al-" therefore assimilates to it. The general rule is that if the initial letter of the word following "al-" is a "sun letter", the "al-" assimilates to it; for "moon letters", no such assimilation takes place.

(found by Google Search on "arabic language al assimilates to following consonant")


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