Why can't I think of the words when speaking?

You may have a condition known as Aphasia, which is a subset of disorders around dementia. Aphasia is caused by the brain shrinking in response to cell death, and usually this affects the part of the brain that controls speech and language. Trouble speaking, writing, typing or understanding words spoken are all symptoms of Aphasia.

If you can't think of words when speaking its a sign of Aphasia, or many other afflictions that are essentially saying your brain is starting to shut down. These symptoms usually affect old people, mostly those in their late sixties to seventies.

Being tired, nervous or fatigued can make it hard for you to think of the right words when speaking. This is normal. However, if this happens on a regular basis, you may have aphasia. This is a communication disorder that makes word retrieval difficult and may affect your ability to talk, write or understand language. Aphasia often results from severe brain injury and is more common in older adults. If this persists, consult a doctor for a proper diagnosis.