Learn Arabic (Modern Standard): انتهى الحديث بين المديرة والموظف. - The conversation between the manager and the employee ended.

The verb انتهى is a Form VIII verb that is intransitive, meaning it doesn't take a direct object. It is used when something ends or finishes on its own (e.g., 'The conversation ended'). If you wanted to say 'The manager ended the conversation', you would use the transitive Form IV verb أنهى, which requires a direct object.

Why do both المديرة (the manager) and الموظف (the employee) take the genitive case (majrur) here?

The word بين (between) functions as a spatial word that creates an idafa (genitive construct) with the noun that immediately follows it. This forces المديرة into the genitive case. Because الموظف is connected to it by the conjunction و (and), it copies the exact same grammatical case.

Both words for the people in this sentence start with a 'mu-' prefix. Is that a coincidence?

Not at all! Both words are derived from verbs using participle patterns, which often start with the 'mu-' prefix. المديرة is a Form IV active participle meaning 'the one who manages' (plus the feminine ending). الموظف is a Form II passive participle, literally translating to 'the one who is employed'.

Is the word الحديث in this sentence related to the religious term 'Hadith'?

Yes, they are the exact same word sharing the root ح د ث. In everyday Modern Standard Arabic, الحديث simply means 'the speech', 'the talk', or 'the conversation'. The Islamic term 'Hadith' uses this same word to specifically refer to the recorded sayings or speech of the Prophet.