I shiggy diggy

Etymology tree
Proto-Indo-European *éǵh₂
Proto-Indo-European *e-
Proto-Indo-European *-m
?
Proto-Indo-European *-óm
Proto-Indo-European *eǵh₂óm
Proto-Germanic *eka
Proto-Germanic *ek
Proto-West Germanic *ik
Old English iċ
Middle English ik, ich, ī
English I
Proto-Indo-European *seh₁-
Proto-Indo-European *-rós
Proto-Italic *sēros
Latin sērus
Proto-Indo-European *-yós
Proto-Italic *-ios
Old Latin -ios
Latin -ius
?
Proto-Indo-European *swer-
Proto-Indo-European *-yós
Proto-Italic *swerjos?
Latin sērius
Proto-Indo-European *h₃ed-
Proto-Indo-European *-os
Proto-Indo-European *h₃édosder.?
Proto-Italic *-ōtsos or *-otsos
Latin -ōsus
Medieval Latin sēriōsus
Old French serieuxbor.
Middle English seryows
Proto-Indo-European *leyg-der.
Proto-Germanic *līkąder.
Proto-Germanic *-līkaz
Proto-Germanic *-ê
Proto-Germanic *-līkê
Proto-West Germanic *-līkē
Old English -līċe
Middle English -lech, -ly
Middle English seryowslech
English seriously
Proto-Indo-European *kewbʰ-
Proto-Indo-European *-néh₂ti
Proto-Indo-European *kubʰnéh₂ti
Proto-Germanic *hup(p)ōnąder.?
Proto-West Germanic *hopōn
Old English hopian
Middle English hopen
English hope
Proto-Indo-European *uswé
Proto-Indo-European *-(m)is?
Proto-Indo-European *uswísder.
Proto-Germanic *izwiz
Proto-West Germanic *iwwiz
Old English ēow
Middle English yow
English you
Proto-Indo-European *dwóh₁
Proto-Indo-European *dwi-
Proto-Indo-European *dʰeh₁-
Proto-Indo-European *h₁weydʰh₁-
Proto-Indo-European *-us
Proto-Indo-European *(h₁)wéydʰ(h₁)us
Proto-Germanic *widuz
Proto-West Germanic *widu
Proto-Indo-European *-ō
Proto-Germanic *-ô
Proto-West Germanic *-ō
Frankish *Widōbor.
Medieval Latin *Widō
Old French Guibor.
English Guy (Fawkes)
English guy
English guys
univ.
English you guys
Proto-Indo-European *dʰeh₁-
Proto-Indo-European *dʰéh₁t
Proto-Indo-European *dʰeh₁-
Proto-Indo-European *dʰédʰeh₁ti
Proto-Germanic *dōną
Proto-West Germanic *dōn
Old English dōn
Middle English don
English do
Proto-Indo-European *né
Proto-Germanic *ne
Proto-West Germanic *ne
Proto-Indo-European *h₂ey-
Proto-Indo-European *-u
Proto-Indo-European *h₂óyu
Proto-Indo-European *-osinflu.
Proto-Germanic *aiwaz
Proto-West Germanic *aiw
univ.
Proto-West Germanic *naiw
Proto-Indo-European *wekʷ-
Proto-Indo-European *-tis
Proto-Indo-European *wékʷtisder.?
Proto-Indo-European *weǵʰ-
Proto-Indo-European *-tis
Proto-Indo-European *wéǵʰtisder.?
Proto-Germanic *wihtą
Proto-West Germanic *wiht
Proto-West Germanic *naiwwiht
Old English nāwiht
Old English *nōht
Middle English nought
Middle English not
English notder.
English -n't
English don't
▲
English do
Proto-Indo-European *só, *to-
Proto-Germanic *sa, *þas
Proto-Germanic *-si
Proto-Germanic *þassi
Proto-West Germanic *þassi
Proto-Anglo-Frisian *þēs
Old English þes
Middle English þis
English this
English I seriously hope you guys don't do thisinit.
English ISHYGDDT
English I shiggy diggy
An intentionally humorous loose rendering of the otherwise unpronounceable initialism ISHYGDDT (“I seriously hope you guys don't do this”), influenced by expressiveness (comparable to expressions like the bomb diggy) and phonetic harmony; compare the etymology of Humvee /Hummer for the same sort of process. Originated on 4chan circa 2011 before spreading to other online communities.