Primary progressive aphasiaPrimary progressive aphasia (PPA) is a type of neurological syndrome in which language capabilities slowly and progressively become impaired. As with other types of aphasia, the symptoms that accompany PPA depend on what parts of the left hemisphere are significantly damaged. However, unlike most other aphasias, PPA results from continuous deterioration in brain tissue, which leads to early symptoms being far less detrimental than later symptoms. Those with PPA slowly lose the ability to speak, write, read, and generally comprehend language.
Specific language impairmentSpecific language impairment (SLI) (the term developmental language disorder is preferred by some) is diagnosed when a child's language does not develop normally and the difficulties cannot be accounted for by generally slow development, physical abnormality of the speech apparatus, autism spectrum disorder, apraxia, acquired brain damage or hearing loss. Twin studies have shown that it is under genetic influence. Although language impairment can result from a single-gene mutation, this is unusual.
AphasiaIn aphasia, a person may be unable to comprehend or unable to formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in the Global North. Aphasia can also be the result of brain tumors, epilepsy, brain damage and brain infections, or neurodegenerative diseases (such as dementias). To be diagnosed with aphasia, a person's language must be significantly impaired in one (or more) of the four aspects of communication.
Speech perceptionSpeech perception is the process by which the sounds of language are heard, interpreted, and understood. The study of speech perception is closely linked to the fields of phonology and phonetics in linguistics and cognitive psychology and perception in psychology. Research in speech perception seeks to understand how human listeners recognize speech sounds and use this information to understand spoken language.
Frontotemporal dementiaFrontotemporal dementia (FTD), or frontotemporal degeneration disease, or frontotemporal neurocognitive disorder, encompasses several types of dementia involving the progressive degeneration of frontal and temporal lobes. FTDs broadly present as behavioral or language disorders with gradual onsets. Common signs and symptoms include significant changes in social and personal behavior, apathy, blunting of emotions, and deficits in both expressive and receptive language.
Speech synthesisSpeech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware products. A text-to-speech (TTS) system converts normal language text into speech; other systems render symbolic linguistic representations like phonetic transcriptions into speech. The reverse process is speech recognition. Synthesized speech can be created by concatenating pieces of recorded speech that are stored in a database.
Speech disorderSpeech disorders or speech impairments are a type of communication disorder in which normal speech is disrupted. This can mean fluency disorders like stuttering, cluttering or lisps. Someone who is unable to speak due to a speech disorder is considered mute. Speech skills are vital to social relationships and learning, and delays or disorders that relate to developing these skills can impact individuals function. For many children and adolescents, this can present as issues with academics. Speech disorders affect roughly 11.
Communication disorderA communication disorder is any disorder that affects an individual's ability to comprehend, detect, or apply language and speech to engage in dialogue effectively with others. The delays and disorders can range from simple sound substitution to the inability to understand or use one's native language. Disorders and tendencies included and excluded under the category of communication disorders may vary by source. For example, the definitions offered by the American Speech–Language–Hearing Association differ from those of the Diagnostic Statistical Manual 4th edition (DSM-IV).
Speech–language pathologySpeech-language pathology (or speech and language pathology) is a field of healthcare expertise practiced globally. Speech-language pathology (SLP) specializes in the evaluation, diagnosis, treatment, and prevention of communication disorders (speech and language impairments), cognitive-communication disorders, voice disorders, pragmatic disorders, social communication difficulties and swallowing disorder across the lifespan.
Developmental language disorderDevelopmental language disorder (DLD) is identified when a child has problems with language development that continue into school age and beyond. The language problems have a significant impact on everyday social interactions or educational progress, and occur in the absence of autism spectrum disorder, intellectual disability or a known biomedical condition. The most obvious problems are difficulties in using words and sentences to express meanings, but for many children, understanding of language (receptive language) is also a challenge.
SpeechSpeech is a human vocal communication using language. Each language uses phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if they are the same word, e.g., "role" or "hotel"), and using those words in their semantic character as words in the lexicon of a language according to the syntactic constraints that govern lexical words' function in a sentence. In speaking, speakers perform many different intentional speech acts, e.
Language disorderLanguage disorders or language impairments are disorders that involve the processing of linguistic information. Problems that may be experienced can involve grammar (syntax and/or morphology), semantics (meaning), or other aspects of language. These problems may be receptive (involving impaired language comprehension), expressive (involving language production), or a combination of both. Examples include specific language impairment, better defined as developmental language disorder, or DLD, and aphasia, among others.
AphasiologyAphasiology 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. 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).
Speech and language impairmentSpeech and language impairment are basic categories that might be drawn in issues of communication involve hearing, speech, language, and fluency. A speech impairment is characterized by difficulty in articulation of words. Examples include stuttering or problems producing particular sounds. Articulation refers to the sounds, syllables, and phonology produced by the individual. Voice, however, may refer to the characteristics of the sounds produced—specifically, the pitch, quality, and intensity of the sound.
Expressive language disorderExpressive language disorder is one of the "specific developmental disorders of speech and language" recognised by the tenth edition of the International Classification of Diseases (ICD-10). As of the eleventh edition (ICD-11, current 1 January 2022), it is considered to be covered by the various categories of developmental language disorder. Transition to the ICD-11 will take place at a different time in different countries. The condition is a communication disorder in which there are difficulties with verbal and written expression.
Statistical classificationIn statistics, classification is the problem of identifying which of a set of categories (sub-populations) an observation (or observations) belongs to. Examples are assigning a given email to the "spam" or "non-spam" class, and assigning a diagnosis to a given patient based on observed characteristics of the patient (sex, blood pressure, presence or absence of certain symptoms, etc.). Often, the individual observations are analyzed into a set of quantifiable properties, known variously as explanatory variables or features.
Speech processingSpeech processing is the study of speech signals and the processing methods of signals. The signals are usually processed in a digital representation, so speech processing can be regarded as a special case of digital signal processing, applied to speech signals. Aspects of speech processing includes the acquisition, manipulation, storage, transfer and output of speech signals. Different speech processing tasks include speech recognition, speech synthesis, speaker diarization, speech enhancement, speaker recognition, etc.
Language delayA language delay is a language disorder in which a child fails to develop language abilities at the usual age-appropriate period in their developmental timetable. It is most commonly seen in children ages two to seven years-old and can continue into adulthood. The reported prevalence of language delay ranges from 2.3 to 19 percent. Language is a uniquely human form of communication that entails the use of words in a standard and structured way. Language is distinct from communication. Communication is a two-stage process.
Speech repetitionSpeech repetition occurs when individuals speak the sounds that they have heard another person pronounce or say. In other words, it is the saying by one individual of the spoken vocalizations made by another individual. Speech repetition requires the person repeating the utterance to have the ability to map the sounds that they hear from the other person's oral pronunciation to similar places and manners of articulation in their own vocal tract.
Receptive aphasiaWernicke's aphasia, also known as receptive aphasia, sensory aphasia or posterior aphasia, is a type of aphasia in which individuals have difficulty understanding written and spoken language. Patients with Wernicke's aphasia demonstrate fluent speech, which is characterized by typical speech rate, intact syntactic abilities and effortless speech output. Writing often reflects speech in that it tends to lack content or meaning. In most cases, motor deficits (i.e. hemiparesis) do not occur in individuals with Wernicke's aphasia.
