Evolutionary Linguistics

        On a weekly radio show about words,
a caller asks about the use of amount
        of versus number of. She is annoyed
when she hears people say things like
        There was a large amount of people 
at the protest rally yesterday, or What
        is the amount of books that have been 
banned under this administration? The show's 
        hosts agree: countable nouns should be
used for things or people to which we can apply
        some discrete unit of measurement;
and uncountable nouns for quantities 
        that can only be measured as a whole, 
like water, or sunlight, or time. But they also 
        remind the caller of how language 
is always evolving— now we use words 
        that used to mean entirely different  
things: a spinster used to refer to someone  
        who spun thread; in "Henry V," there's  
a line that goes I love the lovely bully — apparently, 
        it used to mean sweetheart or darling, not
someone who intimidates or harasses through  
        aggression. There and their, its and it's,
your and you're— same, or different? Mantel, the lintel 
        or decorative shelf above a fireplace, where you 
could put little framed pictures. Mantle, a cloak or 
        shawl; or that part of the earth between 
the surface and its superheated core— where scientists  
        have recently discovered two large, continent-
sized structures. Made of oceanic crust and 
        other unknown elements, they've quietly
thickened under our feet through millennia; and we
        don't know yet how exactly, someday, they'll  
turn inside out everything else we know of this planet.