Plurals and the Dual

Arabic has three number forms: singular, dual, and plural. The plural endings will feel like old friends, the dual will feel like Hebrew's ־ַיִם finally explained, and the famous "broken plurals" will feel like a Hebrew habit taken to its logical extreme.

Sound masculine plural: ون / ين ↔ ־ים

For many masculine nouns (especially people), Arabic adds a suffix: ون (-ūn) when the noun is the subject, ين (-īn) everywhere else. Spoken Arabic simplified this to -īn across the board — and -īn is the direct twin of Hebrew ־ים. Same Proto-Semitic suffix; Hebrew ends it in m, Arabic in n. Aramaic sided with Arabic, which is why Hebrew already carries ־ין in words like נישואין, קידושין and חליפין.

Sound feminine plural: ات ↔ ־וֹת

The dual: Hebrew's ־ַיִם, still on duty

Arabic has a full dual: add ان (-ān) for subjects, ين (-ayn) elsewhere — spoken Arabic keeps only -ēn. The common Semitic ancestor had this for everything; Hebrew kept it only for a frozen list: time words and things that come in pairs. Look at what survived — יומיים, שנתיים, שבועיים, עיניים, ידיים, רגליים. Now look at Arabic: يَوْمَيْن, سَنَتَيْن, أُسْبُوعَيْن, عَيْنَيْن, يَدَيْن, رِجْلَيْن. Hebrew kept the dual for exactly the words Arabic still uses it on. The -ay- core is identical; Hebrew closes it with m, Arabic with n — the same m/n swap as the plural.

Broken plurals: the inside job

Here is the one genuinely new idea. Most Arabic nouns do not take a suffix at all — the plural is formed by rearranging the vowels inside the word: كِتَاب (kitāb) → كُتُب (kutub). Hebrew hints at this concept — בַּיִת becomes בָּתִּים and מֶלֶךְ becomes מְלָכִים, with the inside of the word reshaped before any suffix — but Arabic made internal change the *main system*. The good news: broken plurals fall into a modest set of recurring patterns, and your ear starts predicting them surprisingly fast.