ok = pfontfamily:IsMonospace()
For Western languages this would mean that the advance width of all characters are the same, but this categorization also includes Asian fonts which include double-width characters: characters that occupy two grid cells.
The best way to find out the grid-cell size is to call pfontmetrics:GetApproximateDigitWidth(), since the results of pfontmetrics:GetApproximateCharWidth() may be affected by double-width characters.
True if the family is monospace, False otherwise