Title: Aphasia
Content:  from occasional trouble finding words, to losing the ability to speak, read, or write; intelligence, however, is unaffected. Expressive language and receptive language can both be affected as well. Aphasia also affects visual language such as sign language. In contrast, the use of formulaic expressions in everyday communication is often preserved. For example, while a person with aphasia, particularly expressive aphasia (Broca's aphasia), may not be able to ask a loved one when their birthday is, they may still be able to sing "Happy Birthday". One prevalent deficit in the aphasias is anomia, which is a difficulty in finding the correct word. With aphasia, one or more modes of communication in the brain 
Title: Aphasia
Content:  Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke or head trauma. Aphasia can also be the result of brain tumors, brain infections, or neurodegenerative diseases, but the latter are far less prevalent. To be diagnosed with aphasia, a person's speech or language must be significantly impaired in one (or more) of the four aspects of communication following acquired brain injury. Alternately, in the case of progressive aphasia, it must have significantly declined over a short period of time. The four aspects of communication are auditory comprehension, verbal expression, reading and writing, and functional communication. The difficulties of people with aphasia can 
Title: Aphasia
Content: Inability to comprehend language ; Inability to pronounce, not due to muscle paralysis or weakness ; Inability to speak spontaneously ; Inability to form words ; Inability to name objects (anomia) ; Poor enunciation ; Excessive creation and use of personal neologisms ; Inability to repeat a phrase ; Persistent repetition of one syllable, word, or phrase (stereotypies, recurrent/recurring utterances/speech automatism) ; Paraphasia (substituting letters, syllables or words) ; Agrammatism (inability to speak in a grammatically correct fashion) ; Dysprosody (alterations in inflection, stress, and rhythm) ; Incomplete sentences ; Inability to read ; Inability to write ; Limited verbal output ; Difficulty in naming ; Speech disorder ; Speaking gibberish ; Inability to follow 
Title: Aphasiology
Content:  Aphasiology is the study of language impairment usually resulting from brain damage, due to neurovascular accident—hemorrhage, stroke—or associated with a variety of neurodegenerative diseases, including different types of dementia. It is also the name of a scientific journal covering the area. These specific language deficits, termed aphasias, may be defined as impairments of language production or comprehension that cannot be attributed to trivial causes such as deafness or oral paralysis. A number of aphasias have been described, but two are best known: expressive aphasia (Broca's aphasia) and receptive aphasia (Wernicke's or sensory aphasia).
Title: Aphasia
Content:  Technically, dysphasia means impaired language and aphasia means lack of language. There have been calls to use the term 'aphasia' regardless of severity. Reasons for doing so include dysphasia being easily confused with the swallowing disorder dysphagia, consumers and speech pathologists preferring the term aphasia, and many languages other than English using a word similar to aphasia. It would appear that the term "aphasia" is more commonly encountered in North America, while "dysphasia" is more frequently found in British literature.
Title: Expressive aphasia
Content:  Expressive aphasia, also known as Broca's aphasia, is a type of aphasia characterized by partial loss of the ability to produce language (spoken, manual, or written), although comprehension generally remains intact. A person with expressive aphasia will exhibit effortful speech. Speech generally includes important content words but leaves out function words that have more grammatical significance than physical meaning, such as prepositions and articles. This is known as "telegraphic speech". The person's intended message may still be understood, but their sentence will not be grammatically correct. In very severe forms of expressive aphasia, a person may only speak using single word utterances. Typically, comprehension is mildly to moderately impaired in expressive aphasia due 
Title: Aphasiology
Content:  A person with anomic aphasia have word-finding difficulties. Anomic aphasia, also known as anomia, is a non-fluent aphasia, which means the person speaks hesitantly because of a difficulty naming words and/or producing correct syntax. The person struggles to find the right words for speaking and writing. Subjects tend to use circumlocutions, in which they speak around the word they can not find, to make up for their loss. People also with anomic aphasia tend to know how to use an object, but rather can not name the aforementioned object. Any damage in or near the zone of language can result in anomic aphasia. Other forms of aphasia often transition into a syndrome of primarily anomic aphasia in the process of recovery.
Title: Communication disorder
Content: Acute aphasias ; Expressive aphasia also known as Broca's aphasia, expressive aphasia is a non-fluent aphasia that is characterized by damage to the frontal lobe region of the brain. A person with expressive aphasia usually speaks in short sentences that make sense but take great effort to produce. Also, a person with expressive aphasia understands another person's speech but has trouble responding quickly. ; Receptive aphasia also known as Wernicke's aphasia, receptive aphasia is a fluent aphasia that is categorized by damage to the temporal lobe region of the brain. A person with receptive aphasia usually speaks in long sentences that have no meaning or content. People with this type of aphasia often have trouble understanding other's speech and generally do not realize that they are not making any sense. ; Conduction aphasia ; Anomic aphasia ; Global aphasia ; Primary progressive aphasias ; Progressive nonfluent aphasia ; Semantic dementia ; Logopenic progressive aphasia Aphasia is loss of the ability to produce or comprehend language. There are acute aphasias which result from stroke or brain injury, and primary progressive aphasias caused by progressive illnesses such as dementia.
Title: Aphasia
Content:  understand simple requests People with aphasia may experience any of the following behaviors due to an acquired brain injury, although some of these symptoms may be due to related or concomitant problems, such as dysarthria or apraxia, and not primarily due to aphasia. Aphasia symptoms can vary based on the location of damage in the brain. Signs and symptoms may or may not be present in individuals with aphasia and may vary in severity and level of disruption to communication. Often those with aphasia will try to hide their inability to name objects by using words like thing. So when asked to name a pencil they may say it is a thing used to write. 
Title: Speech and language impairment
Content:  Aphasia refers to a family of language disorders that usually stem from injury, lesion, or atrophy to the left side of the brain that result in reception, perception, and recall of language; in addition, language formation and expressive capacities may be inhibited.

Question: aphasia is a term defining difficulty or loss of ability to?
Answer: comprehend and formulate language.
formulate language.