"Imagine you’re a physician and you are called in to evaluate a patient who has had a sudden change in his neurological status, likely a stroke. You find him alert, mobile, and talking. But when you ask him how he is feeling he says, 'We’re out with them. Other people are working with them and them. I’m very happy with them. This girl with verly good. And happy and I play golf and hit up trees. We play out with the hands. We save a lot of hand on hold for peoples for us. Other hands. I don’t know what you get, but I talk with a lot of hand fram. Sometime. Am I talk of anymore to saying.' You don’t detect any other neurological defects, like weakness or paralysis on one side of the body. What’s going on? Why does he seem so scatterbrained?

If you’re a modern neurologist, you’ll recognize this as a type of aphasia, a common symptom of stroke. You’ll also know that aphasia is a language problem, not an intelligence problem; the patient may be able to think quite clearly but just can’t translate those thoughts into coherent words and sentences. But it took many decades and a great deal of scientific effort to arrive at this modern understanding. Indeed, many physicians practicing a hundred or more years ago would have agreed with French neurologist, Armand Trousseau, who coined the term “aphasia” in the 1860s and claimed that in sufferers of the condition, 'intelligence is always lamed.' Many other prominent clinician-scientists of that era agreed, including the likes of Hughlings Jackson, a leader in early neurology. The view persisted into the 1930s."

Continue reading: https://www.psychologytoday.com/us/blog/wired-for-words/202512/decoding-aphasia-separating-language-from-thought