|فَالَّذِيْ لاَ يَتَغَيَّرُ آخِرُهُ إِمَّا أَنْ يَكُوْنَ مُلاَزِماً لِلسُّكُوْنِ، كَـ”لَمْ”، أَوْ الضَّمَّةِ كَـ”حَيْثُ”، أَو الْفَتْحَةِ كَـ”أَيْنَ”، أَو الْكَسْرَةِ كَـ”بِسْمِ اللهِ”، وَالْمَدَارُ فِيْ تَعْيِيْنِ ذَلِكَ عَلَى النَّقْلِ الصَّحِيْحِ. That whose ending does not change, either adheres (permanently) to: the السُّكُوْن like “لَمْ” (did not),the الضَّمَّة like “حَيْثُ” (where),the الْفَتْحَة like “أَيْنَ” (where), orthe الْكَسْرَة like “بِسْمِ اللهِ” (In the Name of Allah) The method for determining that (i.e. for determining which words are indeclinable) is contingent on sound transmission (based on how previous Arabs used it, and there are no particular rules for logically deriving that).|
You already know that the الْكَلِمَات – when they are grouped together – their ending either adheres strictly to one state or it changes by changing the construction.
Know now that the modes and states that the endings of words have to adhere to do not exceed four: the السُّكُوْن , the الضَّمّ , the الْفَتْح and the الْكَسْر .
Every كَلِمَة whose ending adheres strictly to the السُّكُوْن is said to be: “مَبْنِيَّةٌ عَلَى السُّكُوْنِ” (built or fixed on the السُّكُوْن ), like “لَمْ” (did not), “لَنْ” (will not), “مِنْ” (from), “عَنْ” (of, about), “فِيْ” (in), etc.
Every كَلِمَة whose ending adheres strictly to the الضَّمَّة is said to be: ” مَبْنِيَّةٌ عَلَى الضَّمِّ” (built or fixed on the الضَّمَّة ), like “حَيْثُ” (where), “نَحْنُ” (we), “مُنْذُ” (since, from), etc.
Every كَلِمَة whose ending adheres strictly to the الْفَتْحَة is said to be: ” مَبْنِيَّةٌ عَلَى الْفَتْحِ” (built or fixed on the الْفَتْحَة ), like “أَيْنَ” (where), “لَيْتَ” (hoping, hopefully, perhaps), “ثُمَّ” (then, thereafter), etc.
Every كَلِمَة whose ending adheres strictly to the الْكَسْرَة is said to be: ” مَبْنِيَّةٌ عَلَى الْكَسْرِ” (built or fixed on the الْكَسْرَة ), like the الْبَاء and اللاَّم in your statement: “التَّقَدُّمُ بِالاجْتِهَادِ” (Progress is/comes with diligence) and “لِكُلِّ مُجْتَهِدٍ نَصِيْبٌ” (For every diligent person there is a share/portion).
That a particular كَلِمَة is مَبْنِيَّة on a سُكُوْن , or a ضَمّ , or a فَتْح , or a كَسْر cannot be determined from some rule, rather the method for determining the particular sign on which it is مَبْنِيَّة is contingent on how it has been used in reliable and credible books and by expert users and speakers of Arabic.
When someone says to you: “By what means do you know that “لَمْ” is مَبْنِيّ on the السُّكُوْن , “حَيْثُ” on the الضَّمّ , “أَيْنَ” on the الْفَتْح and the الْبَاء on the الْكَسْر , and why is it not allowed for “لَمْ” to be مَبْنِيّ on the الضَّمّ for example?”
In response to him, you cannot but say that knowledge thereof is not acquired via rules that are learnt, instead it is acquired via oral transmission and hearsay, and that I have not heard the word “لَمْ” in any of the constructions of eloquent and grammatically sound Arabic speech except that its ending has been unvowelled (with a سُكُوْن ), like the statement of the poet:
لَمْ أَخُنْ عَهْداً وَلَمْ أُخْلِفْ وُعُوْداَ
(I did not break a covenant nor did I breach promises)
Hence, based on that you know that “لَمْ” is مَبْنِيَّة on the السُّكُوْن and not on the الضَّمّ nor any of the other الْحَرَكَات (vowel-markings), and because of that I do not pronounce it except as سَاكِنَة (unvowelled with a سُكُوْن ).
Likewise for most indeclinable words (الْكَلِمَات الْمَبْنِيَّة) there is no way of knowing what sign they are مَبْنِيَّة on except through sound transmission, while at the same time it is not difficult for us know that, because the الْكَلِمَات الْمَبْنِيَّة (indeclinable words) in comparison to the الْمُعْرَبَات (declinable words) are very few (in number) and the people’s pronunciation thereof is generally correct, due to the fact that their endings are not subject to change. Even with this in mind, we will still mention those most commonly used among these الْكَلِمَات الْمَبْنِيَّة .