Breakdown of Le estoy contando una broma a mi hermano.
el hermano
the brother
una
a, an (feminine)
estar
to be (location/state)
mi
my
Questions & Answers about Le estoy contando una broma a mi hermano.
Why do we need le in this sentence when it already says a mi hermano?
In Spanish, it is incredibly common (and usually required) to use the indirect object pronoun (le) even when you explicitly state who is receiving the action (a mi hermano). Think of le as a little tag that warns the listener an indirect object is happening, while a mi hermano simply clarifies who the "him" is!
Could I attach le to the end of the verb instead?
Yes! When you use a continuous tense made of two verbs (like estoy contando), you have two choices for where to put the pronoun. You can put it before the conjugated verb, like in this sentence (le estoy contando), or attach it to the end of the action word: estoy contándole. Notice that if you attach it, you need to add an accent mark over the a to keep the pronunciation stress in the right place.
Since contar is a stem-changing verb (yo cuento), why isn't the word cuentando?