essayer de dire
You don't understand what Mary is trying to say.
Tu ne comprends pas ce que Mary essaie de dire.
I am not understanding what the author is trying to say.
Je ne comprends pas ce que l’auteur essaie de dire.
I can't understand what he is trying to say.
Je n’arrive pas à comprendre ce qu’il essaie de dire.
I don't know what Tom was trying to say.
Je ne sais pas ce que Tom essayait de dire.
Tom doesn't understand what Mary is trying to say.
Tom ne comprend pas ce que Mary essaie de dire.
Dad, what are you trying to say?
Papa, qu'est-ce que tu essaies de dire ?
— Eat Drink Man Woman (1994)
Can you make out what he is trying to say?
Arrives-tu à comprendre ce qu’il essaie de dire ?
You don't understand what Mary's trying to say.
Tu ne comprends pas ce que Mary essaie de dire.