Regular and irregular verbs

For information specific to the English language, seeEnglish verbsandEnglish irregular verbs.

For specially constructed "irregular verbs" that satirize uncharitably towards others, seeEmotive conjugation.

Aregular verbis anyverbwhoseconjugationfollows the typical pattern, or one of the typical patterns, of the language to which it belongs. A verb whose conjugation follows a different pattern is called anirregular verb.This is one instance of the distinction betweenregular and irregular inflection,which can also apply to other word classes, such as nouns and adjectives.

InEnglish,for example, verbs such asplay,enter,andlikeare regular since they form their inflected parts by adding the typical endings-s,-ingand-edto give forms such asplays,entering,andliked.On the other hand, verbs such asdrink,hitandhaveare irregular since some of their parts are not made according to the typical pattern:drankanddrunk(not "drinked" );hit(aspast tenseandpast participle,not "hitted" ) andhasandhad(not "haves" and "haved" ).

The classification of verbs asregularorirregularis to some extent a subjective matter. If some conjugationalparadigmin a language is followed by a limited number of verbs, or if it requires the specification of more than oneprincipal part(as with theGerman strong verbs), views may differ as to whether the verbs in question should be considered irregular. Most inflectional irregularities arise as a result of series of fairly uniform historical changes so forms that appear to be irregular from asynchronic(contemporary) point of view may be seen as following more regular patterns when the verbs are analyzed from a diachronic (historical linguistic) viewpoint.

Development

When a language develops some type ofinflection,such as verbconjugation,it normally produces certain typical (regular) patterns by which words in the givenclasscome to make their inflected forms. The language may develop a number of different regular patterns, either as a result of conditionalsound changeswhich cause differentiation within a single pattern, or through patterns with different derivations coming to be used for the same purpose. An example of the latter is provided by the strong andweakverbs of theGermanic languages;the strong verbs inherited their method of making past forms (vowelablaut) fromProto-Indo-European,while for the weak verbs a different method (addition ofdentalsuffixes) developed.

Irregularities in verb conjugation (and otherinflectional irregularities) may arise in various ways. Sometimes the result of multiple conditional and selective historical sound changes is to leave certain words following a practically unpredictable pattern. This has happened with the strong verbs (and some groups of weak verbs) in English; patterns such assing–sang–sungandstand–stood–stood,although they derive from what were more or less regular patterns in older languages, are now peculiar to a single verb or small group of verbs in each case, and are viewed as irregular.

Irregularities may also arise fromsuppletion– forms of one verb may be taken over and used as forms of another. This has happened in the case of the English wordwent,which was originally the past tense ofwend,but has come to be used instead as the past tense ofgo.The verbbealso has a number of suppletive forms (be,is,was,etc., with various different origins) – this is common forcopular verbsin Indo-European languages.

The regularity and irregularity of verbs is affected by changes taking place by way ofanalogy– there is often a tendency for verbs to switch to a different, usually more regular, pattern under the influence of other verbs. This is less likely when the existing forms are very familiar through common use – hence among the most common verbs in a language (likebe,have,go,etc.) there is often a greater incidence of irregularity. (Analogy can occasionally work the other way, too – someirregular English verb formssuch asshown,caughtandspathave arisen through the influence of existing strong or irregular verbs.)

Types of pattern

The most straightforward type of regular verb conjugation pattern involves a single class of verbs, a singleprincipal part(therootor one particular conjugated form), and a set of exact rules which produce, from that principal part, each of the remaining forms in the verb'sparadigm.This is generally considered to be the situation with regularEnglish verbs– from the one principal part, namely the plain form of a regular verb (the bareinfinitive,such asplay,happen,skim,interchange,etc.), all the other inflected forms (which in English are not numerous; they consist of the third person singularpresent tense,thepast tenseandpast participle,and thepresent participle/gerundform) can be derived by way of consistent rules. These rules involve the addition of inflectional endings (-s,-[e]d,-ing), together with certainmorphophonologicalrules about how those endings are pronounced, and certain rules of spelling (such as the doubling of certain consonants). Verbs which in any way deviate from these rules (there arearound 200such verbs in the language) are classed as irregular.

A language may have more than one regular conjugation pattern.French verbs,for example, follow different patterns depending on whether their infinitive ends in-er,-iror-re(complicated slightly by certain rules of spelling). A verb which does not follow the expected pattern based on the form of its infinitive is considered irregular.

In some languages, however, verbs may be considered regular even if the specification of one of their forms is not sufficient to predict all of the rest; they have more than one principal part. InLatin,for example, verbs are considered to have four principal parts (seeLatin conjugationfor details). Specification of all of these four forms for a given verb is sufficient to predict all of the other forms of that verb – except in a few cases, when the verb is irregular.

To some extent it may be a matter of convention or subjective preference to state whether a verb is regular or irregular. In English, for example, if a verb is allowed to have three principal parts specified (the bare infinitive, past tense and past participle), then the number of irregular verbs will be drastically reduced (this is not the conventional approach, however). The situation is similar with the strong verbs inGerman(these may or may not be described as irregular). In French, what are traditionally called the "regular-reverbs "(those that conjugate likevendre) are not in fact particularly numerous, and may alternatively be considered to be just another group of similarly behaving irregular verbs. The most unambiguously irregular verbs are often very commonly used verbs such as thecopular verbbein English and its equivalents in other languages, which frequently have a variety ofsuppletiveforms and thus follow an exceptionally unpredictable pattern of conjugation.

Irregularity in spelling only

It is possible for a verb to be regular in pronunciation, but irregular inspelling.Examples of this are the English verbslayandpay.In terms of pronunciation, these make their past forms in the regular way, by adding the/d/sound. However their spelling deviates from the regular pattern: they are not spelt (spelled) "layed" and "payed" (although the latter form is used in some e.g. nautical contexts as "the sailor payed out the anchor chain" ), butlaidandpaid.This contrasts with fully regular verbs such asswayandstay,which have the regularly spelt past formsswayedandstayed.The English present participle is never irregular in pronunciation, with the exception thatsingeingirregularly retains theeto distinguish it fromsinging.

Linguistic study

In linguistic analysis, the concept of regular and irregular verbs (and other types ofregular and irregular inflection) commonly arises inpsycholinguistics,and in particular in work related tolanguage acquisition.In studies of first language acquisition (where the aim is to establish how the human brain processes its native language), one debate among 20th-century linguists revolved around whether small children learn all verb forms as separate pieces of vocabulary or whether they deduce forms by the application of rules.Since a child can hear a regular verb for the first time and immediately reuse it correctly in a different conjugated form which he or she has never heard, it is clear that the brain does work with rules; but irregular verbs must be processed differently. A common error for small children is to conjugate irregular verbs as though they were regular, which is taken as evidence that we learn and process our native language partly by the application of rules, rather than, as some earlier scholarship had postulated, solely by learning the forms. In fact, children often use the most common irregular verbs correctly in their earliest utterances but then switch to incorrect regular forms for a time when they begin to operate systematically. That allows a fairly precise analysis of the phases of this aspect of first language acquisition.

Regular and irregular verbs are also of significance insecond language acquisition,and in particular inlanguage teachingand formal learning, where rules such as verb paradigms are defined, and exceptions (such as irregular verbs) need to be listed and learned explicitly. The importance of irregular verbs is enhanced by the fact that they often include the most commonly used verbs in the language (including verbs such asbeandhavein English, their equivalentsêtreandavoirinFrench,seinandhabeninGerman,etc.).

Inhistorical linguisticsthe concept of irregular verbs is not so commonly referenced. Since most irregularities can be explained by processes of historical language development, these verbs are only irregular when viewedsynchronically;they often appear regular when seen in their historical context. In the study ofGermanic verbs,for example, historical linguists generally distinguish between strong and weak verbs, rather than irregular and regular (although occasional irregularities still arise even in this approach).

When languages are being compared informally, one of the few quantitative statistics which are sometimes cited is the number of irregular verbs. These counts are not particularly accurate for a wide variety of reasons, and academic linguists are reluctant to cite them. But it does seem that some languages have a greater tolerance for paradigm irregularity than others.

By language

English

With the exception of the highly irregular verbbe,an English verb can have up to five forms: its plain form (or bareinfinitive), a third person singularpresent tense,apast tense(orpreterite), apast participle,and the-ingform that serves as both apresent participleandgerund.

The rules for the formation of the inflected parts ofregularverbs are given in detail in the article onEnglish verbs.In summary they are as follows:

• The third person singular present tense is formed by adding the ending-s(or-esafter certain letters) to the plain form. When the plain form ends with the letter-yfollowing a consonant, this becomes-ies.The ending is pronounced/s/after avoiceless consonantsound (as inhops,halts,packs,bluffs,laughs), or/z/after a voiced consonant or vowel sound (as inrobs,lends,begs,sings,thaws,flies,sighs), but/ɪz/after asibilant(passes,pushes,marches).
• The past tense and past participle are identical; they are formed with the ending-ed,which as in the previous case has three different pronunciations (/t/,/d/,/ɪd/). Certain spelling rules apply, including the doubling of consonants before the ending in forms likeconnedandpreferred.There is some variation in the application of these spelling rules with some rarer verbs, and particularly with verbs ending-c(panic–panicked,zinc–zinc(k)ed,arc–arc(k)ed,etc.), meaning that these forms are not fully predictable, but such verbs are not normally listed among the irregular ones. (The verbslayandpay,however, are commonly listed as irregular, despite being regular in pronunciation – their past forms have the anomalous spellingslaidandpaid.)
• The present participle/gerund is formed by adding-ing,again with the application of certain spelling rules similar to those that apply with-ed.

The irregular verbs of English are described and listed in the articleEnglish irregular verbs(for a more extensive list, seeList of English irregular verbs). In the case of these:

• The third person singular present tense is formed regularly, except in the case of themodal verbs(can,shall,etc.) which do not add-s,the verbbe(which has three present indicative forms:am,isandare), and the three verbshave,doandsay,which produce the formshas,does(pronounced with a short vowel,/dʌz/), andsays(pronounced with a short vowel,/sɛz/).
• The past tense and past participle forms are the forms most commonly made in irregular fashion. About 200 verbs in normal use have irregularities in one or other (or usually both) of these forms. They may derive fromGermanic strong verbs,as withsing–sang–sungorrise–rose–risen,or from weak verbs which have come to deviate from the standard pattern in some way (teach–taught–taught,keep–kept–kept,build–built–built,etc.). (The past participle often ends in "n", "d" or "ed".) The past and past participle forms change in spelling sometimes.
• The present participle/gerund is formed regularly, in-ing(except for thosedefective verbs,such as the modals, which lack such a form).

Common irregular verbs

Some examples of common irregular verbs in English, other than modals, are:

• arise
• be
• come
• do
• eat
• fall
• get
• give
• go
• have
• hear
• know
• lend
• make
• run
• say
• see
• take
• think
• wear
• drink
• put
• cut
• catch
• drive

Other languages

For regular and irregular verbs in other languages, see the articles on the grammars of those languages. Particular articles include, for example:

• Dutch conjugation
• French verbsandFrench conjugation
• German verbsandGerman conjugation
• Ancient Greek verbs(for verbs in Modern Greek, seeModern Greek grammar)
• Irish conjugation
• Italian conjugation
• Japanese verb conjugationandJapanese irregular verbs
• Latin conjugation
• Portuguese conjugation
• Spanish verbs,Spanish conjugationandSpanish irregular verbs
• Welsh has five irregular verbs whose conjugations differ betweenspoken Welshandthe literary language.

Some grammatical information relating to specific verbs in various languages can also be found inWiktionary.

Constructed languages

Mostnatural languages,to different extents, have a number of irregular verbs. Artificialauxiliary languagesusually have a single regular pattern for all verbs (as well as otherparts of speech) as a matter of design, because inflectional irregularities are considered to increase the difficulty of learning and using a language. Otherconstructed languages,however, need not show such regularity, especially if they are designed to look similar to natural ones.

The auxiliary languageInterlinguahas some irregular verbs, principallyesser"to be", which has an irregular present tense formes"is" (instead of expectedesse), an optional pluralson"are", an optional irregular past tenseera"was/were" (alongside regularesseva), and a unique subjunctive formsia(which can also function as an imperative). Other common verbs also have irregular present tense forms, namelyvader"to go" —va,ir"to go" —va(also shared by the present tense ofvader), andhaber"to have" —ha.