What purpose does the author's description of his son's tribal education serve in "an indian father's plea"?

Description:

"He can probably count more than 40 different kinds of birds, tell you and his peers what kind of bird each is and where it lives, the seasons in which it appears, and how it is used in a sacred ceremony. He may also have trouble writing his name on a piece of paper, but he knows how to say it and many other things in several different Indian languages."

Medicine Grizzlybear Lake, "An Indian Father's Plea"

i have heard the mermaids singing, each to each.

i do not think they will sing to me

the characters in string all have major secrets that they strive to avoid revealing throughout the play.