The stems of a verb

The vowel stem and the consonant stem

There are verbs that have no stem variation, such as sanoa used as example in the preceding section. Some verbs have normal consonant gradation but no other stem variation, such as kerto|a : kerto|vat : kerro|taan : kerto|i : kerto|i|vat : kerro|ttiin etc. However, there is also a large number of verbs that have other variation, namely two different stems, called vowel stem and consonant stem. Verbs with such variation may or may not have consonant gradation as well.

At the simplest, the consonant stem is just the vowel stem without its final vowel, e.g. tul- versus tule- in the verb tul|la (to come): tule|n (I come). Some forms, such as the infinitive, are based on the consonant stem, whereas others are based on the vowel stem.

If a verb has a consonant stem, different simplifications take place if that stem would end in a consonant cluster. For example, for the vowel stem juokse- as in juoksen (I run), the cor­re­spond­ing consonant stem is juos-, as in juosta (ro run), not juoks-.

The dictionary form of verbs, I infinitive, is based on the consonant stem, e.g. tulla, juosta. However, it is often natural to treat the vowel stem as primary and the consonant stem as its contraction. On the other hand, some vowel stems are longer than the consonant stem, e.g. harvet|a : harvene|e (to become thinner). For some types of verbs, neither of the two stems is primary; they are just different forms.

The common verb seisoa (to stand) has alternate forms based on the consonant stem seis-, e.g. in the base form seisoa ∼ seistä (or rarely seista) and in the past participle seisonut ∼ seissyt. However, only vowel stem forms are used in the indicative, e.g. seisoo and seisoi, in the conditional, e.g. seisoisi, in the participles seisova and seisoma, in the III infinitive, e.g. seisomassa, except for the instructive seisottaman ∼ seistämän, in the IV infinitive seisominen and seisomista, in the V infinitive seisomaisilla-, and in the imperative 2nd person singular seiso, except that the interjection seis (stop!) can be interpreted as a consonant stem imperative.

Vowel stem forms are sometimes incorrectly used instead of standard Finnish consonant stem forms, e.g. juoksien instead of the correct juosten.

Forms based of the consonant stem

Most verb forms are based on the vowel stem. The following use the consonant stem (with the verb pur|ra : pure|n “to bite” as example):

• I infinitive, e.g. purra, purrakseni
• Ii infinitive, e.g. purren, purressa
• 4th person forms, e.g. purraan, purtiin, purtaisiin, purtaneen
• the common past participles, e.g. purrut, purtu (but not puremani etc.)
• imperative forms except the most common (2nd person singular, pure), e.g. purkoon, purkaamme, purkaa, purkoot, purtakoon
• potential forms, e.g. purren, purret, purree, purremme, purrette, purrevat, purtaneen

Types of stem variation

The following table summarizes the different types of relationships between vowel and consonant stems. Consonant gradation is not covered here.

Verbs of the first type, -AA- : -At, have special features in inflection, discussed in the nect section.

Verbs that end with OidA in the infinitive usually have only one stem, ending with Oi. However, some of them have an alternate longer vowel stem ending with Oitse, which can be used in indicative and condinitional forms. For example, haravoida (to rake) has the 1st person singular form haravoin both in the present tense and in the past tense, but the longer stem lets us distinguish between them: haravoitsen, haravoitsin. Such forms are rare nowadays and may be regarded as dated.