letterAt(text, info) is the letter of a text under the pointer: { index, char, line }, with text.text[index] the one touched, or null on a space, between two letters or outside the text.
Above, a word to spell: each letter touched is added to what is spelled, and touching what is spelled clears it. Below, a line of dialogue broken by maxWidth: touching it says which letter, where it is in the text, on which line, and the whole word around it, found from its index.