Learn Farsi: هیچ‌کس جز دوست من شعار نمی‌داد. - Nobody except my friend was chanting slogans.

In Farsi, when you use a negative pronoun like هیچ‌کس (nobody), the verb must also be negative to match it. The preposition جز (except) exempts your friend from this negative reality. So, while literally saying 'Nobody except my friend didn't chant,' it means your friend was the only one who did.

How is the compound verb for 'chanting slogans' structured in this tense?

The Farsi expression is the compound verb شعار دادن (literally: to give a slogan). To form the past continuous 'was chanting,' you combine the imperfect prefix می with the past stem داد, and add the negative prefix نـ to get نمی‌داد.

Could I use the simple past نداد instead of نمی‌داد here?

You could, but it shifts the focus. نمی‌داد is past continuous, emphasizing that the chanting was an ongoing action in the background ('was chanting'). Using the simple past نداد would describe it as a single, completed event ('chanted').

Does the preposition جز need an ezafe to connect to the next word?

In formal and written Farsi, جز does not take an ezafe, which is why it is simply written as جز دوست من. However, in everyday spoken Farsi, you will often hear people add an ezafe anyway, pronouncing it as جزِ دوست من.