Dr. sardonicus wants to know whether or not the first three years of life are critical for acquiring language. she decides to study a child who was tragically deprived of human language by her parents. this type of research is called a(n)

This type of research is called a "case study".

The term case study alludes to both a strategy for analysis and a particular research plan for looking at an issue, the two of which are utilized by and large to sum up crosswise over populations.  

A case study research paper looks at a man, put, occasion, marvel, or other sort of subject of examination keeping in mind the end goal to extrapolate key topics and results that assistance foresee future patterns, enlighten beforehand concealed issues that can be connected to rehearse, or potentially give a way to understanding a critical research issue with more prominent clearness.

answer; provide for the common defense: