The term ‘reduplication’ refers to a word in which either part or all of the word is repeated. In English, it occurs in several forms:
[1] ‘Baby’ talk, e.g. choo-choo, bye-bye, night-night
[2] Emphasis, e.g. I would never ever do that!
[3] Repetition with a vowel change, e.g. chit-chat, zig-zag,
tick-tock.
[4] Rhyming formations, e.g. super-duper, hocus-pocus,
easy-peasy, nitty-gritty.
In Latin, reduplication occurs in the formation of
[1] some indefinites
quisquis: whoever
quidquid / quicquid: whatever
Since the word is a repetition, both parts decline, but, in
practice, only the nominative forms are commonly found as well as:
quōquō: to wherever / to whatever place
quotquot: however many
Quisquis es, quidquid tibi nōmen est, senex,
summum Iovem deōsque dō testēs (Plautus) │ Whoever you are, whatever your
name is, old gentleman, I call Heaven and God on high to witness
pūrās sibi esse volt aedis: domī quidquid habet,
ēicitur (Plautus) │ He wants his house to be pure: whatever he has at
home is thrown out
Hoc quidem hercle, quōquō ībō, mēcum erit (Plautus) │
This, indeed, by Hercules, wherever I will go, will be with me
Quia certum est mihi, quasi umbra, quōquō tū ībis, tē
semper sequī (Plautus) │ Because I have made up my mind always to follow you,
like a shadow, wherever you go.
Quotquot autem recēpērunt eum dedit eīs potestātem
(Vulgate) │ but as many as / however many received him, he gave them power …
[2] certain pronouns to create emphasis, the first two being
rare:
mēmē: myself
tētē: yourself
sēsē: him / her / itself / themselves
[3] some very common perfect tense verbs; there are two
patterns to note:
[i] Repetition of the initial consonant of the base verb,
followed by e:
cadō (fall) > cecidī
tangō (touch) > tetigī
[ii] Repetition of the initial consonant and the vowel of
the base verb, before the remainder of the perfect stem:
currō (run) > cucurrī
mordeō (bite) > momordī
https://en.wiktionary.org/wiki/Category:Latin_reduplicative_verbs
