Reduplication is the process of repeating a word or part of it to express some grammatical function, plurality for example. It is used in some language families' grammar, most notably in Malayo-Polynesian where it forms plurals:
Bahasa Malay rumah, house, rumah-rumah, houses.
Hawaiian has the important example of Wiki-wiki!
Go, look, Go-go, examine with attention.
- spondeo, spopondi (Latin, "I vow, I vowed")
- λειπω, λελοιπα (Greek, "I am missing, I was missing")
- haitan, haihait (Gothic, "to name, I named")
See also: augment