"redices" and "indices"

[Kragen Javier Sitaker]

I recently corrected someone who used the term "redices" to mean
"reducible expressions" (in the context of the lambda-calculus and
similar formal systems):

    "redices" is not the plural of "redex".  If there were a Latin word
    "redix", it might pluralize as "redices", but there isn't, and
    "redix" is different from "redex" anyway.

He pointed out:

    I think "redices" is fairly common use, as a googling
    confirms. . . . What makes you think "redices" isn't the plural of
    "redex"?  How are you with "indices"?

"Index"
-------

I had to admit that he was right about "index" not being "indix".  I
don't speak Latin myself, but a friend of mine who does explained to
me that "index" and "indices" are the nominative singular and plural
of "index", a regular third-declension Latin noun.  Charlton Lewis's
Latin dictionary has the following entry for it [1]:

    index dicis, m and f [in+DIC-] , one who points out, a discloser,
    discoverer, informer, witness: falsus, S.: haec omnia indices
    detulerunt.-- An informer, betrayer, spy: vallatus indicibus:
    saeptus armatis indicibus: silex, qui nunc dicitur index,
    traitor's stone, O.--An index, sign, mark, indication, proof:
    complexus, benevolentiae indices: vox stultitiae: auctoris
    anulus, O.: Ianum indicem pacis bellique fecit, L.--A title,
    superscription, inscription: deceptus indicibus librorum: tabula
    in aedem cum indice hoc posita est, L.--A forefinger, index
    finger: pollex, non index: indice monstrare digito, H.

I don't know the etymology of the term "redex" for certain, but it
means "reducible expression", and is therefore an originally English
word, not a Latin loanword.  It doesn't appear in the Oxford English
Dictionary Online.

English Pluralization
---------------------

English is somewhat unusual in that it often imports irregular
pluralizations of loanwords along with the original loanwords --- thus
we have mujahedin, Taliban, tableaux, criteria, cherubim, axes, and
bacteria, rather than *mujahids, *Talibs, *tableaus, *criterions,
cherubs, *axises, and *bacteriums. [2] This adds to the confusion of
irregular plurals already natively present in English, things like
"oxen", which was in Old English, coming from Proto-Germanic and
ultimately from Proto-Indo-European. [3] 

As illustrated above, there are many cases in which the regular plural
form is considered incorrect by almost everyone, but there are other
cases where use of the irregular "classical" form is a way to show off
the speaker's erudition; I think "index" and "cherub" are such
examples.  Both "indexes" and "cherubs" are legitimate English, but
"indices" and "cherubim" are ways to demonstrate your erudition, and
perhaps your knowledge of Latin and Hebrew.  Damian Conway's article
"An Algorithmic Approach to English Pluralization" [7] lists several
more examples.

Showing off one's knowledge may be thought to demonstrate an arrogant
attitude of superiority, if those you're talking to don't share that
same knowledge, or to demonstrate that you belong in the group, if
they do.  However, in either case, it's worse if the folks you're
talking to know that the knowledge you're showing off is wrong.

The Jargon File mentions deliberately irregular pluralizations in
hacker jargon [4]:

    Further, note the prevalence of certain kinds of nonstandard
    plural forms. Some of these go back quite a ways; the TMRC
    Dictionary [from the 1950s?] includes an entry which implies that
    the plural of 'mouse' is meeces, and notes that the defined plural
    of 'caboose' is 'cabeese'. This latter has apparently been
    standard (or at least a standard joke) among railfans (railroad
    enthusiasts) for many years.

    On a similarly Anglo-Saxon note, almost anything ending in 'x' may
    form plurals in '-xen' (see VAXen and boxen in the main text)
    [following "oxen"]. Even words ending in phonetic /k/ alone are
    sometimes treated this way; e.g., 'soxen' for a bunch of
    socks. Other funny plurals are 'frobbotzim' for the plural of
    'frobbozz' (see frobnitz) and 'Unices' and 'Twenices' (rather than
    'Unixes' and 'Twenexes'; see Unix, TWENEX in main text). But note
    that 'Unixen' and 'Twenexen' are never used; it has been suggested
    that this is because '-ix' and '-ex' are Latin singular endings
    that attract a Latinate plural. Finally, it has been suggested to
    general approval that the plural of 'mongoose' ought to be
    'polygoose'.

    The pattern here, as with other hackish grammatical quirks, is
    generalization of an inflectional rule that in English is either
    an import or a fossil (such as the Hebrew plural ending '-im', or
    the Anglo-Saxon plural suffix '-en') to cases where it isn't
    normally considered to apply.

    This is not 'poor grammar', as hackers are generally quite well
    aware of what they are doing when they distort the language. It is
    grammatical creativity, a form of playfulness. It is done not to
    impress but to amuse, and never at the expense of clarity.

One might also speculate that hackers do this to poke fun at those who
think that knowing Latin declensions makes them smart.

Other, non-hacker occurrences of the same playful misapplied Latin
pluralization have been reported, such as "grimi" for "grimaces" or
"waitri" for "waitresses". [6]

Back to "Redices"
-----------------

So I can think of six likely interpretations a listener might arrive
at when they hear "redices" used as the plural of "redex":

1. The speaker is trying to demonstrate that they're better-educated
   than I am, but they are failing, because they don't know enough
   Latin to know that "redex" isn't a Latin word.  Therefore, they are
   not only arrogant but unskilled and unaware of it [5].

2. The speaker is trying to demonstrate that they are as well educated
   as I am, but they are failing, because they don't know enough Latin
   to know that "redex" isn't a Latin word.  Therefore, they think
   they are not worthy of associating with me, because they think they
   would need to have a classical education in order to be so, but
   they clearly don't have it.  Furthermore, they are unskilled and
   unaware of it.

3. The speaker uttered an incomprehensible word.  They must have a
   bigger vocabulary than I do; maybe they are smart and I should
   listen to them more carefully.

4. The speaker uttered an incomprehensible word.  They must be talking
   nonsense.

5. The speaker is playfully forming a nonstandard plural.

6. This word "redex" I haven't heard before must be a Latin word, and
   "redices" is either its only correct plural or a correct show-off
   academic plural.

I suspect that explanation #5 is the correct explanation of the term's
origin, and it's prefigured by the "Unices" and "Twenices" examples
from the Jargon File [4], but I intend to avoid the use of "redices"
except in clearly playful contexts because of the possibility of
interpretations #1, #2, #4, and especially #6, which will make it more
difficult for the listener to discover the correct derivation from
"reducible expression".  Maybe this is just me taking myself way too
seriously.

Correcting People
-----------------

If you correct people who are using "redices" (as I did), you run the
risk of a similarly hazardous gamut of responses.

1. Why is he trying to show off his knowledge?  Doesn't he know
   "redices" is a playful invention?  He must be not only arrogant but
   unskilled and unaware of it.

2. I've always heard "redices" as the plural of "redex".  Have I been
   looking dumb all these years?

Oops.

References
----------

These references are not intended to assign credit; they're just here
so you can dig deeper if you're interested.

[1] Charlton Lewis, "An Elementary Latin Dictionary", 1890, ISBN:
0199102058
> http://perseus.mpiwg-berlin.mpg.de/cgi-bin/ptext?doc=Perseus%3Atext%3A1999.04.0060%3Aentry%3D%237793

[2] Letter from Dr. Lim Chin Lam, Penang, to The Star of Malaysia
newspaper, 2006-08-25:

    It must be noted that the above nouns have been adopted (or
    borrowed or hijacked) from other languages and normally retain the
    singular and plural forms in their original language.

> http://thestar.com.my/english/story.asp?file=/2006/8/25/lifefocus/15088814&sec=lifefocus

[3] Douglas Harper's Etymonline Online Etymology Dictionary entry "ox"
> http://etymonline.com/?term=ox

[4] Jargon File 4.2, dated 2000-01-31, attributed to a large
collection of hackers but currently enclosed by Eric Raymond, section
"Jargon Construction", subsection "Overgeneralization";
> http://www.science.uva.nl/~mes/jargon/o/overgeneralization.html

[5] "Unskilled and Unaware of It: How Difficulties in Recognizing
One's Own Incompetence Lead to Inflated Self-Assessments", by Justin
Kruger and David Dunning, published in the Journal of Personality and
Social Psychology, December 1999, Vol. 77, No. 6, 1121-1134
> http://www.phule.net/mirrors/unskilled-and-unaware.html
> http://gagne.homedns.org/~tgagne/contrib/unskilled.html
> http://www.apa.org/journals/features/psp7761121.pdf

[6] "More False Latin", by John Algeo, American Speech, Vol. 41, No. 1
(Feb., 1966), pp. 72-74, doi:10.2307/453250
> http://links.jstor.org/sici?sici=0003-1283(196602)41%3A1%3C72%3AMFL%3E2.0.CO%3B2-G

[7] "An Algorithmic Approach to English Pluralization", by Damian
Conway; this describes the algorithm in Lingua::EN::Inflect.
> http://www.csse.monash.edu.au/~damian/papers/HTML/Plurals.html