In linguistics and etymology, suppletion is the use of one word as the inflected form of another word when the two words are not cognate. Suppletion in a particular language, as demonstrated below, occurs overwhelmingly in lexical items which arise particularly often. Many suppletive forms are known to learners of languages simply as irregular. Broadly conceived, linguistics is the scientific study of human language, and a linguist is someone who engages in this study. ... In historical linguistics, etymology is the study of the origins of words. ... Inflection or inflexion refers to a modification or marking of a word (or more precisely lexeme) so that it reflects grammatical (i. ... Cognates are words that have a common origin. ...

Here are some examples:

• In English, the past tense of the verb go is went, which comes from the past tense of the verb wend, archaic in this sense. (The modern past tense of wend is wended.) There is also a suppletive use of the perfect tense of be to distinguish an experiential sense ("He has been to France") from a resultative sense ("He has gone to France").

• The Romance languages have a variety of suppletive forms in conjugating the verb "to go", as these first-person singular forms illustrate:

Language	Present	Future	Preterite
French	vais (1)	irai (2)	allai (3 or 4)
Italian	vado (1)	andrò (3)	andai (3)
Spanish	voy (1)	iré (2)	fui (5)

The sources of these are 5 different Latin verbs:

1. vadere "to advance"
2. ire "to go"
3. ambulare "to walk" (the source of Spanish andar "to walk")
4. allatus suppletive participle of afferre "to carry"
5. fui suppletive perfective of esse "to be" (the preterites of "to be" and "to go" are identical in Spanish).

• In Germanic languages such as English, and in Romance languages, the comparative and superlative of the adjective "good" is suppletive; in English and the Romance languages, "bad" is also suppletive:

Language	Adjective	Etymology	Comparative/superlative	Etymology
English; German	good; gut	OE gOd, cognate to OHG guod, Sanskrit gadhya "what one clings to"	better/best; besser/am besten	OE betera, cognate to bOt "remedy", Sanskrit bhadra "fortunate"
English	bad	perhaps from OE bæddel "hermaphrodite"	worse/worst	OE wyrsa, cognate to OHG wirsiro
French; Spanish; Italian	bon; bueno; buono	Latin bonus, from OL duenos, cognate to Sanskrit duva "reverence"	meilleur; mejor; migliore	Latin melior, cognate to multus "many", Gk mala "very"
	mauvais; malo; male†	Latin malus	pire; peor; peggiore	Latin pejor, cognate to Sanskrit padyate "he falls"

† This is an adverbial form ("badly"); the Italian adjective is itself suppletive (cattivo, cognate to "captive").

• Similarly to the Italian noted above, the English adverb form of "good" is the unrelated word "well," from Old English wel, cognate to wyllan "to wish."

• In English, the complicated irregular verb be / is / were has forms from several different roots: be originally comes from Indo-European *bhu-; am, is and are from *es-, and was and were from *wes-.

• An incomplete suppletion in English exists with the plural of person (from the Latin persona). The regular plural persons occurs mainly in legalistic use. The singular of the unrelated noun people (from Latin populus) is more commonly used in place of the plural, e.g. "two people were living on a one-person salary" (note the plural verb). In its original sense of "ethnic group", people is itself a singular noun with regular plural peoples.