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Table of Contents

Verbal and Vocal Disabilities

When considering disabilities in the area of verbal communication skills, it is important to distinguish between language (as the verbal basis) and speech (as the vocal form of expression). To understand and produce language is an achievement of our brain. To express this language vocally or also by writing or gestures and thus to communicate is in the broadest sense an achievement of our motor skills (articulation, hand motor skills).

Between these two clearly defined areas there are all those neural structures which are responsible for the conception of movements and for the transmission of nerve signals to the musculature. They form, so to speak, the link between language and speech. Disorders in this area can therefore not always be clearly assigned. In addition, disabilities can also affect both areas of language and speech at the same time, so that a clear classification is impossible in this case. A first classification of the areas in which disorders can occur is given in Table 1 [1, 2].

DysfunctionMotor and sensory dyslalia, phonematic disordersDysgrammatism, problems with determinate sentence constructionsLimited active and passive vocabulary, rare words often not at handInterpersonal communication disorders in social and situational context

Table 1: Disorders in the speech-speech complex.

Disabilities of the Language

Disabilities of language are always based on lesions of the brain or are due to a developmental disorder that has delayed or prevented language acquisition.

  1. Aphasia
    Aphasia is first of all the collective term for all damages occurring after language acquisition and affecting the area of linguistic communication. They can affect both the perception and production of speech. However, aphasia (literally speechlessness) in the narrower sense is usually understood as a disorder of speech production with preserved function of the organs and musculature needed for speech.

    Aphasia often also affects written language and sometimes the expression of gestures or the use of symbols. In this sense, aphasia is a multimodal disability [1, 3]. Aphasia may also affect the ability to understand and produce sign language, as has been found in deaf individuals with lesions of the language areas [4, 5, 6]. The frequency for Western countries is reported to be around 4 out of 1000 (statistics from UK and USA) [2].

    Simple, short and frequently used words, which were learned early in life, have the highest probability of still being mastered despite aphasia. In any case, abstract words, complex syntactic constructions, and the passive form are problematic [5, 6].

    Clinically, aphasia is usually classified as follows, although different opinions exist regarding terminology (for a summary, see Table 2) [7, 8, 1]:

    Amnestic aphasiaWernicke's aphasia
    Sensory A.
    Broca's aphasia
    Motor A.
    Global aphasia
    Speech productionmostly fluentfluentsignificantly slowedscarce to zero, including speech automatisms
    Articulationmostly not disturbedmostly not disturbedoften dysarthricmostly dysarthric
    Prosodymostly well preservedmostly well preservedoften leveled, also chantingoften leveled, mostly well preserved in automatisms
    Sentence constructionbarely disturbedparagrammatism (duplications and entanglements of sentences and parts of sentencesagrammatism (only simple sentence structures, absence of function words)only single-word phrases, speech automatisms
    Word choiceSubstitution strategies for word-finding disorders, some semantic paraphasiasmany semantic paraphasias, often grossly divergent from the target word, semantic neologismsrelatively narrow vocabulary, hardly any semantic paraphasiasextremely limited vocabulary, grossly deviant semantic paraphasias
    Sound structuresome phonemic paraphasiasmany phonematic paraphasias up to neologisms, also phonematic jargonmany phonematic paraphasiasvery many phonematic paraphasias and neologisms
    Comprehensionslightly impairedstrongly disturbedslightly disturbedstrongly disturbed

    Table 2: Classification and leading symptoms of aphasic syndromes according to Poeck, 1994 in [1].

  2. Paraphasia
    Paraphasia refers to a language disorder in which there are omissions, substitutions, additions, or rearrangements. This can occur at the level of phonemes within a word (phonematic paraphasia) or words within a sentence (semantic or verbal paraphasia).

  3. Dysphasia
    Dysphasia (also specific language impairment = SLI) refers to language impairments in brain local syndrome or delayed language development [8]. The impairments often primarily affect verbs (the acquisition, morphology, vocabulary). Verbs with the most general meaning possible are preferred. There is little derivation of semantics (recognizing the meaning of a word) from syntax [9].

  4. Agrammatism, Dysgrammatism
    Agrammatism is a disorder of grammatically correct expression (sentence structure disorder) after completed language development. Speech is in simple, incorrect and often short expressions (telegram style). Conjugations and declensions are missing, often the infinitive is used. Agrammatism refers to the complete absence of syntax in linguistic utterances. Milder forms (especially in childhood grammatical disorders) are called dysgrammatism Occurrence in motor aphasia (see above) and intellectual disabilities.

  5. Alexia, Dyslexia
    Dyslexia is used as a generalized term for a partial reading impairment with otherwise normal overall intelligence. In German-speaking countries, the term Legasthenie or Lese- und Rechtschreibstörung (LRS) is usually used. In affected children, confusion of graphemes[1], faulty spelling, and reduced reading comprehension are noticeable from about the second grade. Dyslexia of various degrees affects between 6 and 10% of children [8]. According to a survey of 700 disabled students at Glasgow University, individuals with dyslexia constitute the largest group [10]. The reasons are still not clear, but both genetic and social influencing factors are suspected [8].

    In the case of dyslexia, it must be noted that reading and spelling disorders can occur together as well as separately. As a rule, arithmetic is not affected. If there is a complete inability to read, it is called alexia. If reading fails due to a lack of recognition of letters, the condition is known as superficial alexia (literary alexia). If, on the other hand, words are not recognized, it is a case of deep alexia or verbal alexia.

    The discussion about dyslexia makes it clear how easily we tend to proceed in terms of “defectology” and talk about impairments and weaknesses without thinking about advantages and strengths. Individuals with dyslexia undoubtedly exhibit weakness in verbalizing, but usually show strengths in visualizing and using pictorial representations of facts. Weaknesses on the constructive side are counterbalanced by strengths in analytical thinking. It may have been these shifts in emphasis that enabled dyslexic individuals such as Faraday or Einstein to achieve the scientific feats that set them apart [11].

  6. Acalculia, Dyscalculia
    A partial performance weakness in dealing with numbers is called dyscalculia or arithmasthenia. If there is a complete inability to calculate, it is called acalculia.

  7. Agraphia
    Similar to reading, writing can also be affected by a partial impairment. An inability to write with intact hand motor skills and normal intelligence is called agraphia.

Impairments of Speech

A weak respiratory system affects the loudness and persistence of vocal utterances. Laryngeal disorders cause breathy, hoarse, soft, whispery, or slowed pronunciation. Dysfunctions of the soft palate result in either overly nasal articulation or absence of nasal sounds. If the anterior articulation system (tongue, jaw, lips) is impaired, the result is slurred, slow, imprecise, or uncoordinated pronunciation. Other articulation disorders may result in varying pitch, fluctuating volume, excessive rate of speech, or disturbances in the rhythm of speech (cluttering, stuttering).

  1. Dysarthria, Anarthria
    Speech disorder caused by paralysis or coordination disorder of the speech muscles as a result of damage to the cranial nerves [12]. The whole complex of voice formation disorders described above is called dysarthria or dysarthrias. Dysarthria can occur as a result of cerebral palsy, muscular dystrophy, apoplexy (cerebral stroke), Parkinson's syndrome, amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), Huntington's disease, brain tumors, myasthenia gravis, or after traumatic brain injury, poisoning, or drug abuse.

    Anarthria refers to the most severe form of dysarthria in which specific articulation of sounds and sentence elements is not possible [12]. Cerebral damage causing dysarthria or anarthria often also causes movement disorders that prevent the affected person from making controlled gestures. This presents an additional obstacle to communication [12].

  2. Aphonia, Dysphonia
    The complete failure of phonation (voice production) is called aphonia. Voice disorders (hoarse, busy, rough voice) and limitation of voice performance is called dysphonia. Causes are, besides psychological influences (shock, stress), various anomalies and diseases of the larynx (also due to injury or intubation).

Disorders in the Border Area Between Language and Speech

Disorders that fall into the border area between language and speech, i.e., in the transition from language conceived in words to sound formation (assignment of phonemes), are deliberately treated here with the speech disorders. Although their causes lie before the actual articulation, this is because the aids used here must not support the language itself, but the pronunciation.

  1. Dyslalia
    Dyslalia is a disorder of articulation in which phonemes are changed or replaced by others. The causes may include central language disorders and delayed language development.

  2. Echolalia
    Echolalia refers to the compulsive verbal or modified repetition of words and sentences heard or said without regard to the content or situation. It is part of natural language development in children between the ages of one and two, but later it is a sign of a language disorder.

  3. Bradylalia
    Bradylalia (also known as bradyarthria or bradyglossia) is a slowing of the speech rate observed, for example, in multiple sclerosis.


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  • Author: Dr. Wolfgang L. Zagler
  • Title: Rehabilitationstechnik
  • Date: March 1, 2008
  • Location: Vienna, Austria
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  1. Grapheme refers to the smallest meaning-bearing unit of written language. ↩︎

List of Abbreviations

United States of America

List of Tables

  • Table 1: Disorders in the speech-speech complex.

  • Table 2: Classification and leading symptoms of aphasic syndromes according to Poeck, 1994 in [1].

List of Sources

  • [1]: Sprach-, Sprech-, Stimm- und Schluckstörungen (Gerhard Böhme, ISBN: 9783437210181)

  • [2]: Practical Simplification of English Newspaper Text to Assist Aphasic Readers (John Carroll, Guido Minnen, Yvonne Canning, Siobhan Devlin, John Tait, Accessed: 2002-04-29)

  • [3]: AUSWEGE - A Computerized Language Therapy Program (Hanspeter Gadler)

  • [4]: Sprache und Gehirn (Antonio R. Damasio, Hanna Damasio)

  • [5]: The Application of Assistive Technology in Facilitating the Comprehension of Newspaper Text by Aphasic People (Siobhan Devlin, John Tait, Yvonne Canning, John Carroll, Guido Minnen, Darren Pearce)

  • [6]: Making accessible international communication for people with language comprehension difficulties (Siobhan Devlin)

  • [7]: Das Puzzlespiel der Neuronen (Claudia Eberhard-Metzger)

  • [8]: Pschyrembel Klinisches Wörterbuch (Willibald Pschyrembel, ISBN: 9783110148244, DOI: 10.1515/9783112328545)

  • [9]: Theory-Based Software Use in Language Interventions (Wilson Mary Sweig, Pascoe Jeffrey P.)

  • [10]: Development Evaluation of a Web-Based Information Service for and about People with Special Needs (Daniela Busse, Stephen Brewster)

  • [11]: A Personal Perspective of Dyslexia (Onya McCausland)

  • [12]: Wortlos Erwachsenwerden (Jeannine Strässle)