In the given diagram:
I. Rectangle represents persons who know English.
II. Triangle represents persons who know Marathi.
III. Square represents persons who know Telugu.
IV. Circle represents persons who know Hindi.


The regions labelled from 1 to 12 represent various combinations of language proficiency among the individuals.
How many individuals can speak English exclusively?

To find the number of individuals who can speak English exclusively, we need to look for the region that lies solely within the rectangle (representing English) and does not overlap with any other geometric shapes (the triangle for Marathi, the square for Telugu, or the circle for Hindi).
Looking at the diagram:

Region 12 is located strictly inside the rectangle.

It is completely outside the circle, triangle, and square.

Therefore, the number of individuals who speak English exclusively is 12.