What is the term for speech that deviates so much from the speech of others that it calls attention to itself, interferes with communication, or produces maladjustment in the speaker?

The correct answer is speech impairment. 

Speech impairment refers to a condition in which an individual is unable to communicate clearly and be coherently understood by others due to difficulties in their speech and articulation. Individuals with speech impairments might be unable to pronounce words correctly, produce speech sounds and speak with abnormal duration, pitch or vocal quality. 

The best sociological research method would have to be using experiments although it has some disadvantages as well