Principal parts
This article is about the grammar term. For the mathematical meaning, see Principal part.In language learning, the
principal parts of a
verb are the series of key forms which the student has to learn by heart in order to be able to conjugate the verb through all its forms.
In
English, the verb
love derives all its forms systematically (
love, loves, loved, loving), and since these can all be deduced from the basic form (the citation or dictionary form, which in English is the
infinitive), no other principal parts have to be learned. With the verb
sing, on the other hand, the forms
sang and
sung cannot be deduced, so the learner of English must memorise three principal parts,
sing – sang – sung. From these, all other forms (like
sings or
singing) can be deduced.
(See also English verbs, English irregular verbs, English as an additional language.)In
Latin, most verbs have four principal parts. The verb "to carry" has the parts
fero – ferre – tuli – latum.
Fero is the first person singular form of the present ("I carry"), but the infinitive
ferre ("to carry") is also needed to deduce all the forms of the present stem. The perfect stem
tuli ("I carried") and the supine stem
latum (required for the perfect passive) are quite irregular in this case, but even with many verbs which are basically regular, they have to be learned in the same way.
In
Spanish, verbs are traditionally held to have only one principal part, the infinitive, by which one can classify the verb into one of three conjugation paradigms (according to the ending of the infinitive, which maybe
-ar,
-er or
-ir). However, some scholars believe that the conjugation could be regularized by adding another principal part to
vowel-alternating verbs, which shows the alternation. For example,
herir "to hurt" is usually considered irregular because its conjugation contains forms like
hiero "I hurt",
hieres "you hurt", where the vowel in the
root changes into a diphthong. However, by including the first person singular, present tense, indicative mood form (
hiero) as a principal part, and noting that the
diphthong appears only when that syllable is stressed, the conjugation of
herir becomes completely predictable.
(See also Spanish verbs, Spanish conjugation.)*
Regular verbs
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Irregular verbs
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Grammatical conjugation*
List of Latin verbs including all four principal parts
