Akkadian has also the same case markers but it is in terms of grammar ( conjugation and almost all prepositions are different) and vocabulary very special.
Yes, but if we're trying to see which of NW Semitic and ASA is closer to Arabic, this is another point in favor of ASA. Now it could be that:
1) Arabic and ASA just happened to retain this case system (and other features like phonology and broken plurals) from Proto-Semitic independently of each other (so ASA, NW and Arabic are three independent branches of West Semitic), or
2) ASA and Arabic share these features because they share a more recent common ancestor that had them (so some sort of SW branch), or
3) Arabic is just a particularly conservative sibling of the NW languages, so that its similarities with ASA are just common Proto-Semitic retentions (like the Akkadian case system) (feels unlikely), or
4) Aramaic is a particularly innovative sibling of Hebrew and Arabic (in which case why are Hebrew and Aramaic grouped together as NW?)
Broken plurals as far as I understand are not an original thing of Semitic languages and mainly developed in the south of Arabia and in some Ethiopic languages as some kind of Sprachbund. Note that even Hebrew has broken plurals, but it consistently adds either -im or -ot to the plural e.g sefer -> sefarim على وزن فِعل التي تصبح فِعال. This phenomenon even exist in some Syrian words e.g. قرقوعة (scrap or useless thing) -> قراقيع qraaqee3 -> قراقعين qraaq3een
As
@radagasty said, this Hebrew plural form is probably not a broken plural at all, and certainly can't be compared to the very extensive and well developed system of Arabic. Is the South Arabian (e.g. Sabean) plural system similar to the Arabic one? If it is, then that seems like pretty strong evidence for a closer relationship. The Ancient North Arabian languages also seemed to have broken plurals, which I think adds weight here.
By the way, the قراقعين example occurs in some Najdi dialects too (كبير > كبار > كبارين). Seems like just a 'plural of a plural' that arises independently and doesn't indicate any shared retention with Hebrew.
I highly recommend you to follow Ahmad Al-Jallad on Twitter if you have not already. Here is him reading some
Sabaic if you are interested.
I do and I'm half-way through one of his papers on South Arabian languages. Does he tackle this question of classification/genetic descent directly anywhere?
If I were to use Islamic genealogical terminology, I would say this sounds like an old Qahtanite Arabic while ours is the Ishmaelite version influenced by the Semitic tongues of the Levant hence the association to Hebrew. Taxonomically, of course, they're all sister languages having inherited features independently and having influenced eachother through geography with northern Arabic dialects acting as a bridge inbetween westerly groups.
No please not the genealogical terminology!
This was the conflation that caused people like Taha Hussein to think that Imru' Al-Qays didn't speak Arabic so couldn't have composed Arabic poetry. Most of the tribes the genealogists called "Qahtanite" (including the real-life historical Qahtan) spoke North Arabian Arabic. Only a few were described as speaking "Himyarite" languages. The Muslim scholars never claimed that the Qahtanites spoke another language (they thought the Qahtanites taught Arabic to the Adnanites). It was only in modern times that early orientalists and their disciples like Taha Hussein made the logical leap that North Arabian vs. South Arabian languages is equivalent to Adnanite v. Qahtanite tribal genealogies, and so they thought Qahtanite = South Arabian and Qahtanite language = South Arabian language.
But yes I agree the simplest explanation is that North Arabian languages (like Arabic) are a sort of intermediate form between NW languages of the Levant like Canaanite/Hebrew and Ancient South Arabian languages like Sabaic. If I were to venture to guess, I would say there was an early West Semitic speaking group in the Levant that split off and migrated south and became the Ancient South Arabians, and a group that migrated south slightly later whose language became Arabic, and perhaps a third a group that stayed in the Levant (or returned there early on) whose language became some of the other Ancient North Arabian dialects (like Safaitic). And then areal influence pulled the Arabic inside the peninsula towards South Arabian and pulled the other Ancient North Arabian dialects towards Aramaic. You probably also had later Arabic tribal migrations from inside the Peninsula before Islam (like the Iyad, Tanukh, Lakhm, Ghassan, Kalb, Jutham, Taghlib, etc.) bringing the Arabic we know today and and continuing until modern times, where older groups and dialects are displaced by dialects from the interior.