Take That is an English pop musicians consisting of members Gary Barlow, Howard Donald, Jason Orange, Mark Owen, and, formerly, Robbie Williams. All perform primarily on vocals though each have some instrumental talent/song-writing capability….

Since it’s impossible to violate Wikipedia’s copyright, here, in its long glory, is a very interesting excerpt on irregular plurals from Latin and Classical Greek from Wikipedia’s entry on English Plurals. I hope you all will enjoy it as much as I did.

English has borrowed a great many words from Latin and Classical Greek. The general trend with loanwords is toward what is called Anglicization or naturalization, that is, the re-formation of the word and its inflections as normal English words. Many nouns (particularly ones from Latin) have retained their original plurals for some time after they are introduced. Other nouns have become Anglicized, taking on the normal “s” ending. In some cases, both forms are still competing.

The choice of a form can often depend on context: for a librarian, the plural of appendix is appendices (following the original language); for physicians, however, the plural of appendix is appendixes. Likewise, a radio engineer works with antennas and an entomologist deals with antennae. Choice of form can also depend on the level of discourse: correctly formed Latin plurals are found more often in academic and scientific contexts, whereas in daily speech the anglicized forms are more common. In the following table, the Latin plurals are listed, together with the Anglicized forms when they are more common.

* Final a becomes -ae (also -æ), or just adds -s:

alumna alumnae
formula formulae/formulas
encyclopædia encyclopædias (encyclopædiae is rare)

* Final ex or ix becomes -ices (pronounced [ɪˌsiːz] or [əˌsiz]), or just adds -es:

index indices /ˈɪndɪˌsiːz/ or indexes
matrix matrices /ˈmeɪtɹɪˌsiːz/
vertex vertices /ˈvɜːtɪˌsiːz/,/ˈvɝtɪˌsiːz/

Some people treat process as if it belonged to this class, pronouncing processes /ˈpɹɑsɪˌsiːz/ instead of standard /ˈpɹɑsɛsɪz/. Since the word comes from Latin processus, whose plural is again processus, but now with a long u (fourth declension), this pronunciation is without etymological basis.

* Final is becomes es (pronounced [ˌiːz]):

axis axes /ˈækˌsiːz/
crisis crises /ˈkɹaɪˌsiːz/
testis testes /ˈtɛsˌtiːz/

Note that axes, the plural of axis, is pronounced differently from axes (/ˈæksɪz/), the plural of ax(e).

* Final ies remains unchanged:

series series
species species

* Final on becomes -a:

automaton automata
criterion criteria
phenomenon phenomena (more below)
polyhedron polyhedra

* Final um becomes -a, or just adds -s:

addendum addenda
agendum agenda (agenda is now a common shortening for a list of agenda, and has its own plural, agendas)
datum data (Now usually treated as a singular mass noun in both informal and educated usage, but usage in scientific publications shows a strong UK/US divide. U.S. usage prefers treating data in the singular in all contexts, including serious and academic publishing. UK usage now widely accepts treating data as singular in standard English, including educated everyday usage, at least in non-scientific use. UK scientific publishing usually still prefers treating it as a plural. Some UK university style guides recommend using data for both singular and plural use, and some recommend treating it only as a singular in connection with computers.)
In engineering, drafting, surveying, and geodesy, and in weight and balance calculations for aircraft, a datum (plural datums or data) is a reference point, surface, or axis on an object or the earth’s surface against which measurements are made.
forum fora/forums
medium media (in communications and computers; now often treated as a singular mass noun)/
mediums (spiritualists, or items of medium size etc.)
memorandum memoranda/memorandums

* Final us becomes -i (second declension, [aɪ]) or -era or -ora (third declension), or just adds -es (especially in fourth declension, where it would otherwise be the same as the singular):

alumnus alumni
corpus corpora
focus foci
genus genera
prospectus prospectuses (plural prospectus is rare)
radius radii
viscus viscera

Virus had no plural ending in Latin; the plural in English is usually viruses. See plural of virus.
cactus cactuses/cacti (in Arizona many people avoid either choice with cactus as both singular and plural.)
fungus fungi
hippopotamus hippopotamuses/hippopotami
octopus octopuses (note: octopi also occurs, although it is strictly speaking unfounded, because it is not a Latin noun of the second declension, but rather a Latinized form of Greek ὀκτώπους. The theoretically correct form octopodes is rarely used.)
platypus platypuses (same as octopus: platypi occurs but is etymologically incorrect, and platypodes, while technically correct, is even rarer than octopodes)
terminus termini/terminuses
uterus uteri/uteruses

Colloquial usages based in a humorous fashion on the second declension include Elvii to refer to multiple Elvis impersonators and Loti, used by petrolheads to refer to Lotus automobiles in the plural.

* Final as in one case of a noun of Greek origin changes to -antes:

Atlas Atlantes (statues of the hero); but
atlas atlases (map collections)

* Final ma in nouns of Greek origin can add -ta, although -s is usually also acceptable, and in many cases more common.

stigma stigmata/stigmas
stoma stomata/stomas
schema schemata/schemas
dogma dogmata/dogmas
lemma lemmata/lemmas