Irregular verbs

English has many irregular verbs, and at first, there seems to be no rhyme or reason in these verbs. However, historically, irregular verbs can be put into different groups, and these verbs are listed here for those interested.

First things first, it is important to know that irregular verbs can be split mainly into two categories of conjugation: strong and weak. The difference is:


 * Strong verbs form their past tense and past participle forms with a change in vowel, and the past participle ends (or formerly ended) with -en. This change in vowel is called ablaut.
 * Weak verbs need an additional ending such as -ed for their past tense and past participle forms.

There are also two other categories: preterite-present and "anomalous". Verbs of those two categories are few, but are nonetheless among the speech's commonest verbs.

Strong verbs
See here.

Weak verbs
See here.

Preterite-present
In Proto-Germanic, there were certain verbs commonly thought to have come from the Proto-Indo-European perfect, but these verbs came to have present significance. For example, the archaic verb wit (meaning know) is akin to Latin videō (I see), and it is not hard to see how past sight of something implies present knowledge thereof. Hence, these verbs have the same form in the first and third-person singular present, unlike normal verbs. Most of these verbs came to be used as modal auxiliaries.

The preterite-present verbs (showing their Old English forms and their modern descendants) are:

Notes:


 * Can, may, and shall are defective verbs, as they no longer have infinitives or participles.
 * Can originally meant know, which later became know how to, whence its current meaning of be able to.
 * May originally meant have the power to do, whence its current meanings of possibility and permission. The original meaning of may can be found in the related noun might.
 * Shall originally meant owe, whence its current meaning of obligation and current use as a future tense auxiliary.
 * Must was originally the past tense form of mōtan (which would have normally become moot), but it was used so often as a past subjunctive that it became a present-tense auxiliary, whence the lack of any distinct past tense form.
 * Owe is now a regular verb and is no longer used as an auxiliary.
 * Owe originally meant have, possess, and so own, originally the past participle, became an adjective, and the regular verb own was later formed.
 * Owe later shifted in meaning from possession to obligation, whence the current meaning of ought. Ought was the past tense of owe, but it was used so often as a past subjunctive that it became its own verb, and it is now used only as an auxiliary of present meaning.
 * Dare is now a regular verb when not used as an auxiliary. The past tense form durst is now archaic.
 * Wit, meaning know, has a full conjugation as well while keeping the irregularity in its forms, much like be, but it is not used as an auxiliary. The verb is now archaic, but it survives in (un)witting and to wit.
 * Dow is a dialectal verb meaning thrive, prosper. Its past tense form is dought.
 * OE munan means remember, and the infinitive would have become mun.
 * OE nugan is found only in the derivatives benugan and genugan (both of which have unattested infinitives). Benugan means require, and genugan means suffice and is related to the adjective enough. The infinitive would have become now.
 * OE þurfan means need, require, and in the negative, it means not have to, which makes it the opposite of must not. The infinitive would have become thurve.
 * OE unnan means grant, allow, and the infinitive would have become un.
 * Sometimes, the verb need is conjugated as if it were a preterite-present, and so one may see such phrases as he need not go and need I say any more?. This use is confined to questions and grammatically negative phrases in the present tense, and it is still usual to treat need like a regular verb, e.g., he does not need to go, do I need to say any more?.

Anomalous
There are some verbs that are truly irregular, as they do not belong to any of the aforesaid classes. There are only four: be, do, go, and will.

Be, the English tongue's most irregular verb, is historically a blend of two different verbs: bēon and wesan. From the bēon conjugation are:


 * The infinitive, imperative, and present subjunctive, be.
 * The present participle, being.
 * The past participle, been.

And from the wesan conjugation are:


 * The first-person singular present indicative, am.
 * The second-person singular present indicative, art.
 * The third-person singular present indicative, is.
 * The plural present indicative, are.
 * The first and third-person singular past indicative, was.
 * The second-person singular past indicative, were (later changed into wast and wert).
 * The plural past indicative and subjunctive, were.
 * The past singular subjunctive, were (the second-person form later changed into wert).

These forms came from many originally distinct verbs.

The past tense of do, did, was originally formed by reduplication of the stem, which makes do the only surviving verb whose past tense came from reduplication. The past participle, done, is straightforward, as it has the past participle ending -en.

The past tense of go was originally yede, but it soon became replaced by went, which was the past tense of the weak verb wend (which now generally uses wended as the past tense). The past participle is gone, which has the usual past participle ending.

Will (distinct from the regular verb will as in God willed it so), unlike the other modal verbs, is not a preterite-present verb. The past tense is would, but the verb has no past participle (both in Old English and in New English), nor has it now an infinitive or present participle. The verb originally was a normal verb meaning desire (like its German cognate wollen), but later came to be used as an auxiliary not only to show desire but also to refer to the future.