Suppletion

In linguistics, suppletion is the use of two unrelated words as forms of the same word where other words use a more regular pattern of inflection or derivation. Suppletion is most common among the most common words in a language. The definition of "suppletion" used here may be somewhat broader than some linguists use.

Dimensions of suppletion
Nouns may show suppletion by number: one person but two people, or Polish człowiek "person" but ludzie "people", except in specific formal contexts where persons is used. Mass noun forms may be suppletive as well: cattle and swine. Likewise verbs: I am and he is (from Proto-Germanic *wesanan) but we are and they are (from Proto-Germanic *iranan). English lost its dual number long ago, but traces of duals occur in dual-plural suppletive pairs: either vs. any and both vs. all.

Suppletion of nouns by gender is widespread as well: boy vs. girl, bull vs. cow, and especially mother vs. father (universal 1657). Third-person pronouns are the same way: he vs. she. Occasionally, this can cause insensitivity when no one can agree on a gender-neutral alternative.

Among adjectives that agree with nouns, articles are probably the most likely to show suppletion. The definite article in Dutch is suppletive by number and gender: het (neuter/diminutive singular) is related to "it", while de (animate singular and all plurals) is related to English "the".

Suppletion may happen based on a verb's tense, with present tense using one form and past tense using another. The verb for to go in English, Spanish, and French differs by tense, with the English past tense deriving from an archaic verb to wend, and the Spanish present va "he goes" and past fue "he went" from "to advance" and "to be". Defective verbs replace missing forms with periphrastic forms of other verbs. The English modal verbs are suppletive in non-finite forms: present can, past could, infinitive be able to, participle been able to.

Suppletion may happen based on a verb's voice, with a different verb form depending on which participant in an action is the subject. One example is English to give, whose indirect object is the subject of to get or to obtain. There are a ton of English verbs that mean to trade, each marking a different participant as the subject. Voice suppletion also happens in Greek.

Almost all languages' personal pronouns are suppletive by person. Only a few show alternation that parallels the demonstratives such as the koitsu paradigm of personal pronouns in Japanese, which translate literally as "this person" or "that person", but even in Japanese, those are not the most common pronouns.

Verbs may show suppletion based on the person of one or more arguments. The English of Shakespeare's era had I am and he is vs. thou art (same derivation as are), and until sometime in the twentieth century, English had I shall vs. he will. This is not limited to the subject; some languages have suppletion on some verbs by the person of another argument. Several languages have different verbs for "give to me", "give to you", and "give to him", and some Oto-Manguean languages have it for "say" based on to whom something is said (rarum 114). The Paleosiberian language Ket even swaps out "say" for the subject's gender (rarum 146).

The most common adjectives almost always have different positive and negative forms: "good" vs. "bad", "long" vs. "short", "right" vs. "wrong". The only exceptions here appear to be constructed languages such as Esperanto and Newspeak. The comparative forms of the most common among these are likely to differ from the base form: better and best vs. good; worse and worst vs. bad.

Many languages have suppletion for the smallest ordinal numbers compared to the corresponding cardinals. For example, the ordinal forms of English one and two are first and second, which come from words meaning "foremost" and "following" respectively, while third and fourth come from the same roots as three and four. And among cardinals, the smallest numerals used in counting ("one, two, three") may not be related to those for describing quantities ("two dogs"). This is common for "one" and much rarer for "two" (rarum 115).

Languages may have suppletion for the fruit from a particular plant, or some plants and not others. In English, a pine tree produces pine cones, a hazel produces hazelnuts, and a soy plant produces soybeans, but an oak produces an acorn, and a bramble produces a blackberry. The fictional language Lapine, on the other hand, derives these more regularly: a brek ("bramble") produces a brekennion (blackberry), and a mayth ("oak") produces a maythennion (acorn). English derives some words for meat from the animal, such as fish, chicken, and rabbit, but it uses suppletion with largely French loans for animals eaten by the Anglo-Normans and for invertebrates: beef from a cow, pork from a hog, mutton from a sheep, and escargot from a snail.

Suppletion may happen for adjective forms of a noun: pig but porcine. This sort of suppletion happens in English with distantly related words, one native and one borrowed: cow but bovine, horse but equine, tree but arboreal. This tendency of English to borrow adjectives from an international prestige language has led at least one writer to call English "defective" and inspired an "Anglish" movement to repopularize English words not borrowed from Latin. But at least it gives the backronym bovine stool (from "BS") as a nicer way to say bullshit.