Inner speech varies from constant to absent across people. Anendophasia names complete lack of inner speech experience. Low inner speech predicts worse verbal working memory performance. Anendophasics struggle more with rhyme judgments from images. Task switching shows no link to inner speech levels. Anendophasia parallels aphantasia and synesthesia in phenomenal variation. Studies confirm behavioral deficits tied to absent inner speech. Human phenomenal experiences form a vast unexplored space.