If your loved one is having difficulty understanding you, write out key words and phrases while you talk. For example ask, "What would you like for lunch? Soup or a sandwich?" while writing "soup" and "sandwich." Point to each word while you say it. This will help with comprehension, while also activating reading and speaking centers in the brain.
You may feel that your family member's understanding is intact, when in actuality it may be more impaired than you realize. You may become upset because they don't seem to respond to what you are saying, or that they are "forgetting" what was just discussed. People with aphasia may react appropriately during social situations, which gives the impression that they understand the conversation.
This may be a successful communication situation on the surface, and it is not to say that they do not understand some of the message; however, your family member may be picking up on facial expressions and other cues that conversational partners are providing. Some people with aphasia may need frequent visual references to help them understand, especially when there are many speakers involved.
Gesture frequently when you are talking, like an informal sign language in which your gesture represents the idea or object. Examples of this would be using your hand in a cutting motion for "cut", your finger to your temple when saying "think", or pointing to the cake when you talk about it "Do you want some cake?"