My advisor was intrigued to see the peak in archaic words at the beginning of Chapter 9.  Here is the graph of those words superimposed on the uncommon word graph.

Since the archaic words are a subset of the uncommon words, we know that the scale must be smaller; in this case it’s about one-twentieth the scale of the red graph (who scale is shown over on the left).  Where you see the red and green graphs equal, that means there’s one archaic word in every twenty uncommon ones.

While we have the leisure, let’s break down each of those archaic peaks.

• Archaic words in the troll peak:  laden merrily merry canny lout glimpses merrily merry merry
• Archaic words in the leap-in-the-dark peak: glimpse orcs glimpse bewildered glimpsed
• Archaic words in Mirkwood: glimpses accursed merry merrily lob lob merrymaking eldest kinsfolk merrily merrymaking merry merry yonder merry merry kine mead glimpse merry
• Archaic words in Chapters 17 through the end: bewilderment kinsmen alas, kinsfolk merrily merry merrier merry bewildered elder wrought unwrought merrier merry merry merry laden merry merry merry merry merry merry elders

Well!  We seem to have a merriment detector working for us!  And the word merry we can use broadly as an elf-detector!  Everything we have had to say about archaic words is tagged here, and the concordance entry for “Merry” is right here.

My original thought was that archaic words – tagged by the OED as “obsolete”, “archaic”, “rare”, “colloquial” – would indicate high register.  These words certainly contribute – but their numbers are too few to be a robust finding.  We will take the clue about elves and tuck it away for consideration.