Irregular plural nouns |– foreign plurals | The parts of speech | Grammar | Khan Academy Video Lecture | Complete Course on English Grammar: Upgrade your Speaking & Listening - Personal Skills

hello grammarians today we're talking
about another kind of irregular plural
noun and that is the foreign plural
those are words that are borrowed into
English from some other language words
like fungus or cactus or thesis or
criteria and these words come from Latin
and Greek respectively but don't get the
idea that you need to learn to be able
to speak Latin or Greek in order to
speak English no not at all but while
some words that got borrowed into
English have lost their language
specific plurals some have not some have
maintained those plurals and it kind of
depends on which situation you're using
them in so for example in an informal
context it would be perfectly acceptable
for you or me to say funguses like that
but if I was talking to a biologist she
would probably say fungi if she were
talking about them in a scientific
context just like it's okay in informal
speech to talk about cactuses you're
driving a long road in Arizona you see a
lot of cactuses but again if you studied
cactuses for living you would probably
call them cacti it's more precise it's
more formal if you like it's more polite
now my feeling is that as fungus and
cactus get more and more entrenched into
English eventually these formal endings
are going to fall away and we're just
going to have this regular plural but
for now there are still some pluralizing
rules for other languages that it helps
to know so let's go through those so I
made this little chart to go over the
six most common Latin and Greek
irregular plurals that you're going to
encounter in English so the first one is
final a to final AE so you take a word
like larva in the singular which is like
a little baby bug like an ant larva or a
caterpillar larva and the traditional
irregular plural the Latin plural of
that is larvae AE but the regular plural
that will probably get more popular over
time is larvas but this is the first one
a to AE larvae to larvae just like
antennae becomes antennae
secondly the ending change from final us
to final I which we find in a word like
fungus is the singular and then the
irregular plural of that is fungi and as
I said before there are some people who
use funguses but again that regular
plural is more informal this next one is
also Latin and it's the change from
final um to final a so we take a word
like datum which is a single unit of
data so the plural of data so we change
singular datum to plural data and there
is no accepted you wouldn't say that
data's that is not a an accepted regular
plural I think what's going to happen
instead is that datum is going to fall
away but again it hasn't really happened
yet not in a not in a formal context
anyway this next one is also Latin and
its final e^x or final IX - final icees
so if you take a word like index or
matrix the plural of that is not indexes
but indices indexes is again the
informal regular plural but indices is
the more formal irregular plural
likewise matrices this one is Greek and
it's the change from final is to final
es as in the word thesis in the singular
becoming theses in the irregular plural
the regular plural this I do not care
for because it is thesis --is and I
think that sounds silly but thinking
something is silly is no reason to stand
a thwart the tide of linguistic change
grumble grumble this last one is also
Greek and it's the change from singular
Oh n - plural a so we take the this word
like criterion or phenomenon and in the
plural it is criteria or phenomena
do-do-do-do-do and as with datum there
isn't really a regular plural form for
criteria nobody says criterions because
the word criteria is so much better
known anyway so these are six little
ending rules
like I said you don't need to learn
Latin or Greek in order to make sense of
English but having these six rules in
your tool belt if you use them
judiciously will probably come in handy
but for real if you see a word and you
don't know its derivation just trust
your instincts and give it a regular
plural just tack on an S you know the
world's not going to end no harm will
come to you and if you're curious you
can look it up later you can learn
anything David out