Brain infarction leading to unclear speech is a form of incomplete motor aphasia due to cerebral infarction, a speech dysfunction usually seen in lesions on the left side of the brain. Speech dysfunction includes motor aphasia, sensory aphasia and mixed aphasia, and motor aphasia includes incomplete motor aphasia and complete motor aphasia. Complete motor aphasia means that the patient is unable to speak, but is able to understand the meaning of what is being said. Incomplete motor aphasia means that the patient does not speak clearly, but is able to understand the meaning of others’ speech. Mixed aphasia means that the person is unable to speak or understand what is being said. Sensory aphasia means that the patient is able to speak, but is not able to understand what is being said. In patients with cerebral infarction, if there is unclear speech, the patient may also have sensory and motor impairment of the right limb.