-phasia

Also ‑phasic.

Speech disorder.

Greek phanai, to speak.

Psychologists use these terms for speech disorders that are mainly caused by brain damage. Examples are aphasia (Greek a‑, not), inability, or impaired ability, to understand or produce speech; dysphasia (Greek dus‑, difficult), deficiency in the generation of speech, and sometimes also in its comprehension; paraphasia (Greek para, amiss, irregular), jumbling of words and production of meaningless sentences.

Associated adjectives are formed in ‑phasic: aphasic, dysphasic. However, some in that ending derive instead from nouns ending in ‑phase, for example biphasic, having two phases, or polyphasic, consisting of or occurring in a number of separate stages.