Anendophasia
The absence of inner speech — no internal monologue. Thoughts arrive without being narrated in words. Distinct from aphantasia but often discussed alongside it as another form of internal-experience atypicality.
Some people have a running inner monologue that narrates their thoughts; others experience thinking as something wordless. Anendophasia describes the absence of inner speech in particular. Thoughts still occur — they are present, structured, and usable — but they do not pass through language before being expressed. People with anendophasia often describe their thinking as conceptual or spatial rather than verbal, and may notice that the words for an idea form only as they begin to speak.
There is overlap in the population — some people without visual imagery also lack inner speech — but the two are independent phenomena. A 2024 study by Nedergaard and Lupyan in Psychological Science found that adults with low or absent inner speech performed less well on certain verbal working-memory and rhyme-judgement tasks than those with typical inner speech, while performing comparably on most other cognitive measures. The trait does not impair general intelligence or reasoning, but it may shape which cognitive strategies feel natural.
Anendophasia is not a disorder; it is not in the DSM or the ICD. The research on it is younger than the research on aphantasia, and prevalence estimates are still being refined.