Mental sub-normality has been posing problems to every society in various ways and the society has been trying to help mentally subnormal in order to help itself. But inspite of being a very important and burning problem, not much attention has been paid to understand the adjustment and speech problems of the group. Mentally subnormal children due to their limited mental capacities are bound to face difficulties into their adjustment in different aspects of life in comparison to normally developed children.
Mental sub-normality is characterized predominantly by an intellectual's endowment below the normal and is usually present since birth, soon after birth or foetal abnormality during pregnancy.
The subnormal child cannot derive benefit from teaching methods of ordinary school, but requires a special attention and training.
Problems of mentally subnormal children attracted the attention of educational authorities throughout the World, especially in France and lot of work started in this direction of construction of intelligence tests to classify the pupils in a special group.
As yet little is known concerning the type and frequency of occurrence of behavioral problems during their interaction with social groups at different stages of social development. They are maladjusted not only at their schools, but also at home, health and emotional spheres of life.
The most common handicap of the subnormal children is poor speech, which results in poor communication and leads to disturbed inter-relationship with parents, teachers and other groups. It also affects ability to be taught, to learn, interact and communicate in the society. Thus, it brings a person to a stage of broken individuality, which is isolated from society. As a result they suffer from emotional disturbance and try to cope in every aspect of life in a maladaptive and immature manner. The present study attempts to throw some light on these problems. Twenty-five mentally subnormal adolescents (between 14-18 age range) served as the subject of this study. The sample was selected from the schools for mentally subnormal at Lucknow. They came from different socio-economic status.
In twenty-five adolescents of average intelligence between the age range of 14-18 years were selected from two Inter Colleges of Kanpur. They also belonged to different socio-economic status groups.
In this study purposive type of sampling was used in selection of the samples. Both the groups were matched in regard to age, religion, I.Q and socio-economic status.
For assessing the intellectual potentiality of the subjects Stanford Binet Test was administered and for knowing the adjustment problems: Hindi Adaptation of Bell's Adjustment Inventory was used to assess the frequency & intensity of speech defects among mentally sub normal group. A self-made proforma for speech disorder was applied.
Socio-economic status scale (urban) by Kappuswamy was applied to know the socio-economic status of the subjects on the basis of his or her father's:

a. Education
b. Occupation
c. Income.
The data obtained from the study was analyzed to find out the mean standard deviation and percentage of various variables.
To find out significance of differences between the means of the two groups `T' test was used. Results are presented through Table

Table I:

Showing mean and standard deviation of the adjustment scores in home, health, social and emotional areas are total adjustment sense of the mentally subnormal group.

Table II:

Showing mean and standard deviation of the adjustment scores in home, health, social and emotional areas and total adjustment score of the normal group.

Table III:

Showing means of I.Q. and means of total adjustment scores of mentally subnormal and normal groups.

Table IV:

Showing the association between the ranges of I.Q., mean of total adjustment and also decrement in frequency of speech defects as I.Q. range increases..

Table V:

Showing relationship between levels of socio-economic status, means of total adjustment and also with frequency of speech defects in mentally subnormal group.