Sarah, Thank you for sharing your experience and concern. As I read your comment, I immediately thought of my husband. He gets transient aphasia symptoms during his attack cycles frequently. It was very frustrating for him, and it was concerning as well. His symptoms come and go and are more pronounced in the prodrome and postdrome phases. Since we know this happens during an attack cycle and that it resolves it is less worrisome for us. He will commonly replace the word that he means with another word unrelated to the context, or he will say a word that rhymes with the word he means to say. Other times, he will lose the thought train and be silent for several seconds. Aphasia is a symptom that many people living with migraine disease report. Here is a link to an article he wrote a few years ago that speaks about his experience with brain fog and aphasia.
https://migraine.com/living-migraine/aphasia-brain-fog
I'm sorry you are experiencing this frustrating and scary symptom; you are not alone. I hope you find comfort in that and always know we are here to support you! We are here for you—warmly, Cheryl, migraine community team.