Chapter 13: Turning Latin Verbs into Latin Adjectives

§87. The Latin suffixes -BILIS (> E -ble) and -ILIS (> E -ile)

Before reading this chapter, you might be well advised to review Chapter 5 (summary in §41), where you learned how a variety of suffixes can be attached to Latin NOUN bases in order to form derived adjectives. A closely parallel process occurs with VERBS, using an altogether different set of suffixes.[1] Once again, the Latin categories are reflected quite systematically in their English derivatives. Since the principle is one that we have now seen many times, the less important types will be presented with a minimum of comment.

There are two suffixes that convey the idea “able to be,” when joined either to a present or perfect verb base.

  • The first is -BILIS, which is linked to the verb base by a stem vowel: -a- for the 1st conjugation, and -i- for the rest. Thus the 1st conjugation verb laudare (“praise”) gave rise to the adjective laud-ā-bilis (“able to be praised”) > English laudable. This Latin loan-word is very close in meaning to the English hybrid praiseworthy.[2] The 4th conjugation verb audire (“hear”) produced aud-ĭ-bilis (“able to be heard”) > English audible. Similarly, portable (< L port-ā-bilis) means “able to be carried”; and visible  (< L vis-ĭ-bilis) means “able to be seen.” Notice that the suffix usually expresses a PASSIVE rather than an ACTIVE meaning; that is to say, audible conveys the notion “able to be heard,” not “able to hear.” Sometimes an active meaning is apparent, as in the adjective stable (< L sta-bilis), “able to stand.”[3] Occasionally the suffix has a slightly different force, as in horrible (< L horr-ĭ-bilis < horrēre, “shudder”), which suggests “able to cause a shudder” (L horror).

From Latin present infinitive bases we get such English adjectives as tangible (L tangibilis < tangĕre, “touch”); credible (L credibilis < credĕre, “believe”); con-vertible and in-contro-vertible (L vertibilis < vertĕre, “turn”). From Latin perfect participle bases come visible (L visibilis < vidĕre, visus); flexible (L flexibilis < flectĕre, flexus, “bend”); and risible (L risibilis < ridēre, risus, “laugh”). Soluble (late Latin solubilis) is a slightly irregular derivative of solvĕre, solutus, “loose.”

Unfortunately, a knowledge of Latin will not provide an infallible[4] guide to English spelling. As we saw with Latin present participles, the process of French transmission can confuse the conjugation rules. Thus English has forms such as tenable and movable, both derived from 2nd conjugation verbs in ēre. Moreover, in modern English usage -able is treated as a standard suffix that can be added to almost any verb, whether Latin or Germanic in origin; accordingly, we have transferable, manageable, workable, and a host of other adjectives that have no original Latin counterpart.

  • The second suffix is -ILIS,[5] identical in usage to -bilis. Alongside of tangible, we have the adjective tactile (L tactilis < tangere, tactus), which has exactly the same etymological meaning, “able to be touched.” In English, tactile has acquired a special meaning, “pertaining to the sense of touch.” Although the adjective frangible does exist in English, we more often use fragile (L fragilis, “able to be broken” < frangere, fractus, root frag-). Etymologically, docile (L docilis < docere, “teach”) means “able to be taught”; today it is a virtual synonym for tractable (L tractabilis < tractare), “able to be handled.” Agile (L agilis) has an active meaning: “able to act” or “do” (agere). A missile is “able to be sent” (mittere, missus), whereas a projectile is “able to be thrown forward” (pro-jicere, pro-jectus). Can you work out the etymological meanings of ductile, tensile, reptile, versatile, and volatile?

Both the -bilis and -ilis adjective types could form nouns in -itas, as suggested by our words portability, visibility, agility, and fragility (= frailty). Many such English forms, however, are modern coinages, including all hybrids like workability.

  1. This chapter deals only with DEVERBATIVE adjectives formed by the use of suffixes. Don’t forget that the perfect participle, the present participle, and the gerundive are all verbal adjectives, as well; in their case, one may say that the verb stem itself is modified, rather than augmented by a suffix.
  2. It is called a hybrid because the etymon of praise is Latin pretiare (“to value”), a denominative verb from pretium. The English words praise, prize, and price are all close relatives.
  3. The stable in which farm animals are kept is a homograph derived from L sta-bulum (a “stand thing”); see §74, number 4.
  4. < L fallĕre, “deceive.”
  5. This morpheme did not have the same Latin pronunciation as the -īlis that was attached to nouns (e.g., sen-īlis, “like an old man”), since the deverbative suffix had a short -ĭ- (e.g., agĭlis).


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Greek and Latin Roots: Part I - Latin by Peter Smith (Estate) is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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