What is the term for difficulty in speaking or understanding language?

The term for difficulty in speaking or understanding language is aphasia. Aphasia is a language disorder that affects a person's ability to communicate. This can manifest as difficulty in speaking, understanding spoken language, as well as reading and writing. It often occurs after brain injury, especially to areas of the brain responsible for language processing, such as Broca's or Wernicke's areas.

Dysphasia, often viewed as a milder form of aphasia, refers specifically to difficulties with the production or comprehension of speech, but it is not as severe as aphasia, which is why aphasia is the more accurate choice when referring broadly to problems with language. Dyslexia, on the other hand, relates specifically to difficulties in reading and writing. Dysarthria involves issues with the physical mechanics of speech rather than the cognitive processing of language.

In this case, while dysphasia is aligned with language comprehension and production difficulties, the broader and more accurate term encompassing all aspects of language impairment is aphasia.