"My grandmother lives in my house."
Translation:جَدَّتي تَسْكُن في بَيْتي.
Actually both are the same ... (Taskunu).
You (m) live: أنتَ تَسْكُنُ (anta taskunu).
She lives: هِيَ تَسْكُنُ (hiya taskunu).
In such instances, adding the pronoun could be useful to clarify and remove any ambiguity, but generally speaking if the speaker and receiver know the topic, on many occasions the pronouns can be dropped. Pronouns are also added sometimes to add emphasis to some level even if there is no ambiguity.