The World Health Organisation defined medical prevention in 3 stages.

relates to all activities aimed at "reducing the incidence of a disease within a population and therefore reducing, whenever possible, the risks of new cases". Applied to speech and language this means mainly information and health education, as well as training of all those professionals dealing with a specific population.

relates to all activities aimed at "reducing the prevalence of disease and therefore reducing the time of evolution". Applied to Speech and Language, this means mainly screening and early detection of delays or disorders. Early detection and treatment may lead to the elimination of the disorder or to the reduction of the disorder’s progress.

aims at "reducing the prevalence of chronic disabilities or recurrence of a disease, thus reducing the functional modalities due to the disease". In Speech and Language disabilities it relates to management of the problem including various techniques of rehabilitation and intervention aiming at preventing further problems arising as a result of a disorder.
Speech and language therapists/ logopedists have, in their history, most commonly provided tertiary prevention. In recent years practice of primary and secondary prevention has become an increasing part of the work of the profession, as has multidisciplinary teamworking. Examples of what this practice can be are given here.
A necessary step to optimise prevention is to include strategies of prevention in all initial SLT’s/logopedists’ education programmes and to give legal competence in it to these professionals as it already is in many European countries.

Many measures can be taken to prevent speech or language impairments. Many preventive measures have a medical basis and are implemented prior to the birth of a baby. Far example, polio and rubella can have devastating effects an an unborn baby; proper immunization protects adults and children from these and other diseases. A nutritional supplement of folic acid during pregnancy can reduce the risk of cleft palates and lips by 25 to 50 percent (Maugh, 1995). Proper prenatal care is important to the health of babies. Good nutrition influences the strength and early development of very young children.
The link between poverty and disabilities is clear (CDF, 2004). Those who are poor are less likely to have access to information and medical programs, which puts them at risk for diseases that result in disabilities (Utley & Obiakor, 2001). The availability of proper medical care before and after birth is crucial. Access to health care during childhood is important so that diseases in early childhood, such as measles and otitis media, can be avoided or treated early. Better public education programs available to the entire population inform people of the necessity of good prenatal care, nutrition, and medical care. Innovative approaches to the dissemination of information about the importance of protecting children from disease can make real differences in reducing the numbers of individuals who have language problems because they did not receive immunizations or early treatment for illness. For example, TV or radio advertisements may reach some families; different approaches might be more effective when informing other families. Health fairs sponsored by churches, sororities, fraternities, and other community organizations may prove to be more effective than traditional means in communicating important information to the African American community (CDF, 2004).