Arabic verbs ( ; ), like the verbs in other Semitic languages, and the entire vocabulary in those languages, are based on a set of two to five (but usually three) consonants called a root (triliteral or quadriliteral according to the number of consonants). The root communicates the basic meaning of the verb, e.g. 'write', 'read', 'eat'. Changes to the vowels in between the consonants, along with prefixes or suffixes, specify grammatical functions such as person, gender, number, tense, mood, and voice.
Various categories are marked on verbs: Three tenses (present, past; future tense is indicated by the prefix or the particle and the present tense). Two voices (active, passive) Two genders (masculine, feminine) Three persons (first, second, third) Three numbers (singular, dual, plural) Six moods in the non-past only (indicative, subjunctive, jussive, imperative, and short and long energetics) Nineteen forms, the derivational systems indicating derivative concepts such as intensive, causative, reciprocal, reflexive, frequentative etc. For each form, there is also an active and a passive participle (both adjectives, declined through the full paradigm of gender, number, case and state) and a verbal noun (declined for case; also, when lexicalized, may be declined for number).
Weakness is an inherent property of a given verb determined by the particular consonants of the verb root (corresponding to a verb conjugation in Classical Latin and other European languages), with five main types of weakness and two or three subtypes of each type.
Arabic grammarians typically use the root to indicate the particular shape of any given element of a verbal paradigm. As an example, the form (root: ك-ت-ب) 'he is corresponded (with)' would be listed generically as (yuta1ā2a3u), specifying the generic shape of a strong Form VI passive verb, third-person masculine singular present indicative.
The maximum possible total number of verb forms derivable from a root — not counting participles and verbal nouns — is approximately 13 person/number/gender forms; times 9 tense/mood combinations, counting the س- future (since the moods are active only in the present tense, and the imperative has only 5 of the 13 paradigmatic forms); times 17 form/voice combinations (since forms IX, XI–XV exist only for a small number of stative roots, and form VII cannot normally form a passive), for a total of 1,989. Each of these has its own stem form, and each of these stem forms itself comes in numerous varieties, according to the weakness (or lack thereof) of the underlying root.
Inflectional categories Each particular lexical verb is specified by four stems, two each for the active and passive voices. In a particular voice, one stem (the perfective stem) is usually used for the past tense, and the other (the imperfective stem) is usually used for the present and future tenses, along with non-indicative moods, e.g. subjunctive and imperative. Though there is still some disagreement about the interpretation of the stems as tense or aspect, the dominant current view is that the stems represent aspect, sometimes of a relative rather than absolute nature. In this system of classification, the ostensibly "past" and "non-past" stems are called the perfective stem and imperfective stem.
To the past stem, suffixes are added to mark the verb for person, number and gender, while to the non-past stem, a combination of prefixes and suffixes are added. (Very approximately, the prefixes specify the person and the suffixes indicate number and gender.) A total of 13 forms exist for each of the two stems, specifying person (first, second or third); number (singular, dual or plural); and gender (masculine or feminine).
There are six separate moods in the non-past: indicative, imperative, subjunctive, jussive, short energetic and long energetic. The moods are generally marked by suffixes. When no number suffix is present, the endings are for indicative, for subjunctive, no ending for imperative and jussive, for shorter energetic, for longer energetic. When number suffixes are present, the moods are either distinguished by different forms of the suffixes (e.g. for masculine plural indicative vs. for masculine plural subjunctive/imperative/jussive), or not distinguished at all. The imperative exists only in the second person and is distinguished from the jussive by the lack of the normal second-person prefix .
The third person masculine singular past tense form serves as the "dictionary form" used to identify a verb, similar to the infinitive in English. (Arabic has no infinitive.) For example, the verb meaning 'write' is often specified as , which actually means 'he wrote'. This indicates that the past-tense stem is ; the corresponding non-past stem is , as in 'he writes'. Using the third person masculine singular as the dictionary citation form is more useful in that the vowels that appear in the remaining present tense forms are evident. Especially in form I verbs, without prior knowledge, these vowels are often not evident based purely on the past-tense forms.
Tense
There are three tenses in Arabic: the past tense ( ), the present tense ( ) and the future tense. The future tense in Classical Arabic is formed by adding either the prefix or the separate word onto the beginning of the present tense verb, e.g. or 'he will write'.
In some contexts, the tenses represent aspectual distinctions rather than tense distinctions. The usage of Arabic tenses is as follows: The past tense often (but not always) specifically has the meaning of a past perfective, i.e. it expresses the concept of 'he did' as opposed to 'he was doing'. The latter can be expressed using the combination of the past tense of the verb 'to be' with the present tense or active participle, e.g. or 'he was writing'. There are some special verbs known as "compound verbs" that can express many grammatical aspects such as Inchoative, Durative etc., for example means "he started to attract attention" which badaʾa conveys the meaning of "to start doing something (in the past)" The two tenses can be used to express relative tense (or in an alternative view, grammatical aspect) when following other verbs in a serial verb construction. In such a construction, the present tense indicates time simultaneous with the main verb, while the past tense indicates time prior to the main verb. (Or alternatively, the present tense indicates the imperfective aspect while the past tense indicates the perfective aspect.)
In all but Form I, there is only one possible shape for each of the past and non-past stems for a given root. In Form I, however, different verbs have different shapes. Examples: 'write' 'earn' 'read' 'turn' 'become big, grow up' Notice that the second vowel can be any of in both past and non-past stems. The vowel occurs in most past stems, while occurs in some (especially intransitive) and occurs only in a few stative verbs (i.e. whose meaning is 'be X' or 'become X' where X is an adjective). The most common patterns are: past: ; non-past: or past: , non-past: (when the second or third root consonant is a "guttural," i.e. one of ) past: ; non-past: past: ; non-past:
Mood
There are three moods ( , a word that also means "cases"; ), whose forms are derived from the imperfective stem: the indicative mood ( ), usually ending in ; the subjunctive ( ), usually ending in ; and the jussive ( ), with no ending. In less formal Arabic and in spoken dialects, the subjunctive mood is used as the only imperfective tense (subjunctivism) and the final ḥarakah vowel is not pronounced.
The imperative ( ) (positive, only 2nd person) is formed by dropping the verbal prefix (ت-) from the imperfective jussive stem, e.g. 'present!'. If the result starts with two consonants followed by a vowel ( or ), an elidible (ا) is added to the beginning of the word, usually pronounced as "", e.g. 'wash!' or 'do!' if the present form vowel is , then the alif is also pronounced as , e.g. 'write!'. Negative imperatives are formed from the jussive.
The exception to the above rule is the form (or stem) IV verbs. In these verbs a non-elidible alif ا pronounced as is always prefixed to the imperfect jussive form, e.g. "send!", When a verb in Arabic ends with a vowel, the vowel is replaced with the corresponding short vocal when converted into imperative. 'add!'.
The subjunctive is used in subordinate clauses after certain conjunctions. The jussive is used in negation, in negative imperatives, and in the hortative +jussive. For example: 2. m.: imperfect indicative 'you are doing' subjunctive 'that you do' jussive its meaning is dependent upon the prefix which attaches to it; in this case, it means 'may you do not do!' short energetic its meaning is dependent upon the prefix which attaches to it; if the prefix is "la" it means 'you should do' long energetic it has more emphasis than the short energetic, its meaning is dependent upon the prefix which attaches to it; if the prefix is "la" it means 'you must do' imperative 'do!'.
Voice
Arabic has two verbal voices ( "forms", ), active ( ), and passive ( ). The passive voice is expressed by a change in vocalization. For example: active 'he did', 'he is doing' passive 'it was done', 'it is being done'
Thus, the active and passive forms are spelled identically in Arabic; only their vowel markings differ. There are some exceptions to this in the case of weak roots.
Participle Every verb has a corresponding active participle, and most have passive participles. E.g. 'teacher' is the active participle to stem II. of the root ('know'). The active participle to Stem I is , and the passive participle is . Stems II–X take prefix and nominal endings for both the participles, active and passive. The difference between the two participles is only in the vowel between the last two root letters, which is for active and for passive (e.g. II. active , and passive ).
Verbal noun (maṣdar)
In addition to a participle, there is a verbal noun (in Arabic, , , literally meaning 'source'), sometimes called a gerund, which is similar to English gerunds and verb-derived nouns of various sorts (e.g. "running" and "a run" from "to run"; "objection" from "to object"). As shown by the English examples, its meaning refers both to the act of doing something and (by frequent semantic extension) to its result. One of its syntactic functions is as a verbal complement of another verb, and this usage it corresponds to the English gerund or infinitive (He prevented me from running or He began to run). verbal noun formation to stem I is irregular. the verbal noun to stem II is . For example: 'preparation' is the verbal noun to stem II. of ح-ض-ر ('to be present'). stem III often forms its verbal noun with the feminine form of the passive participle, so for , 'he helped', produces the verbal noun . There are also some verbal nouns of the form : , 'he strove', yields 'striving' (for a cause or purpose).
Some well-known examples of verbal nouns are (see Fatah) (Form I), (Form II), (Form III), (Form IV), (feminine of Form VIII verbal noun), and (Form X).
Derivational categories, conjugations The system of verb conjugations in Arabic is quite complicated, and is formed along two axes. One axis, known as the form (described as "Form I", "Form II", etc.), is used to specify grammatical concepts such as causative, intensive, reciprocal, passive or reflexive, and involves varying the stem form. The other axis, known as the weakness, is determined by the particular consonants making up the root. For example, defective (or third-weak or final-weak) verbs have a or as the last root consonant (e.g. 'throw', 'call'), and doubled (or geminated) verbs have the second and third consonants the same (e.g. 'extend'). These "weaknesses" have the effect of inducing various irregularities in the stems and endings of the associated verbs.