Learn French: J'attends son appel depuis hier. - I have been waiting for his call since yesterday.

In French, if an action started in the past and is still happening right now, you use the present tense along with depuis. Because you are still waiting, it is treated as a present action.

Why is there no word for 'for' after J'attends?

The French verb attendre already means 'to wait for'. You never need to add a preposition like pour after it. You just attach the thing you are waiting for directly.

Could son appel mean 'her call' instead of 'his call'?

Yes! In French, possessive adjectives agree with the gender of the noun being owned, not the gender of the owner. Because appel is masculine, you use son regardless of whether a man or a woman is calling.

Why use depuis here instead of pendant?

Depuis connects a past starting point to an action that is still going on in the present. It translates to 'since' when used with a specific point in time, like depuis hier, or 'for' with a duration. You would use pendant for a duration of time that has already ended.