Anxiety dreams can be caused by worries, fears and stress during your day. A dream triggered by anxiety can be a re-mix of old memories, or an invention of pieces of imagery which you had seen before as a bystander, or had seen before in fiction or on the screens.
If you dream about speaking with a different accent, it can mean you faced extreme stress during your day. You may have felt misunderstood or out of place. This thought and feeling have invaded your subconsciousness and triggered a dream about speaking in a different accent.