Allen and Greenough's New Latin Grammar for Schools and Colleges
J. B. Greenough, G. L. Kittredge, A. A. Howard, Benj. L. D'Ooge, Ed.

In many the simple verb is incomplete, but the missing parts occur in its compounds: as, vādō , vādere , in-vāsī, in-vāsum.

Some verbs occur very commonly, but only in a few forms:—

[*] a. Âiō, I say:—

The vowels a and i are pronounced separately (a-is, a-it） except sometimes in old or colloquial Latin. Before a vowel, one i stands for two (see § 6. c):—thus âiō was pronounced ai-yō and was sometimes written aiiō.

[*] b. Inquam, I say, except in poetry, is used only in direct quotations (cf. the English quoth).

The only common forms are inquam , inquis , inquit , inquiunt , and the future īnquiēs , inquiet .

[*] c. The deponent fārī, to speak, has the following forms:—

Several forms compounded with the prepositions ex , prae , prō , inter , occur: as, praefātur , praefāmur , affārī , prōfātus , interfātur , etc. The compound īnfāns is regularly used as a noun (child). īnfandus , nefandus , are used as adjectives, unspeakable, abominable.

[*] d. Queō, I can, nequeō, I cannot, are conjugated like eō . They are rarely used except in the present. Queō is regularly accompanied by a negative. The forms given below occur, those in full-faced type in classic prose. The Imperative, Gerund, and Supine are wanting.

[*] Note.--A few passive forms are used with passive infinitives: as, quītur, queuntur, quitus sum , queātur , queantur , nequītur, nequitum; but none of these occurs in classic prose.

[*] e. Quaesō, I ask, beg (original form of quaerō ), has—

[*] Note.--Other forms of quaesō are found occasionally in early Latin. For the perfect system ( quaesīvī , etc.), see quaerō (§ 211. d).

[*] f. Ovāre, to triumph, has the following:—

[*] g. A few verbs are found chiefly in the Imperative:—

1. PRES. singular salvē, plural salvēte , FUT. salvētō, hail! (from salvus, safe and sound). An infinitive salvēre and the indicative forms salveō , salvētis , salvēbis , are rare.
2. PRES. singular avē (or havē ), plural avēte , FUT. avētō, hail or farewell. An infinitive avēre also occurs.
3. PRES. singular cĕdo, plural cĕdite ( cette ), give, tell.
4. PRES. singular apage, begone (properly a Greek word).