The question was raised on Auxlang whether the Esperanto J-plural
used for both adjectives and nouns is the same independent phoneme.
Here's an example which I throw out for consideration.

Recently I showed my two-year-old son that if you take two mirrors
such as what we have in our bathroom cabinet, and position them
in a certain way with your head inbetween them, you see about 6
reflections of your head.  My son really likes this.  He calls it
"tri Gxonaj".  I don't think we ever said anything like that to him

So, assuming that he made this up himself, a child that can't really
count to 6 can figure out that:
        - J is a plural ending.
        - when applied to nouns that end in "a", it's pronounced "aj"
          (and not 'o' 'on' 'oj' or 'ojn')

I suppose an alternate explanation is that he thinks his name
is an ajective, and that he's a "Gxona" (jonish?) person -- so
"tri gxonaj" means "three Jonish ones."

I find the first explanation easier to believe.

Thomas - Rochester NY USA