Germanic verb
The Germanic verb system carried two innovations over the previous Indo-European verb system:
- Simplification to two tenses: present (also conveying future meaning) and preterite.
- Development of a new way of indicating the preterite and past participle, using a dental suffix.
Later Germanic languages developed further tenses periphrastically, that is, using auxiliary verbs, but the constituent verbs of even the most elaborate periphrastic constructions are still only either in present or preterite (cf I would have had with would in preterite).
There are three classes of Germanic verbs: vocalic (using vowel-alternation or ablaut, which comes from Indo-European, cf Greek leipo vs leloipa vs elipon), consonantal (using a dental suffix) and preterite-present (present tense looking like a vocalic preterite, originally from an Indo-European perfect, and preterite with dental suffix). In addition, there is a class of reduplicating verbs, which shows clearly in Gothic, but in the later Germanic languages was assimilated into the vocalic paradigm and became a vocalic class of its own.
Vocalic verbs
The Indo-European vowel-alternations could be as follows:
- ei — oi — i
- eu — ou — u
- e — o — (zero)
- o — ō — a
In Germanic, these became the following classes:
- ī — ai — i
- iu — au — u/o
- e/i — a — u/o
- a — ō — a
In the last class there was also a lengthened grade with ē
In Gothic we find these forms:
- dreiban (ei = ī) — draif (3sing) — dribun (3pl) — dribans (past participle)
- biudan — bauþ — budun — budans
- hilpan (from *helpan) — halp — hulpun — hulpans
- qiman (from *qeman) — qam — qemun (e = ē) — qumans
- faran — for (o = ō) — forun (o = ō) — farans
In addition, we find a class of reduplicating verbs, with or without vowel alteration:
- haitan — haihait (=hehait) — haihaitun (=hehaitun) — haitans
- tekan — taitok — taitokun — tekans
In the later Germanic languages, the reduplicating class became a distinct vocalic class, for example in Old English:
- fallan — feoll — feollon — (ge)fallen
- hātan — hēt — hēton — (ge)hāten
Or Old High German:
- fallan — fiall — fiallun — (gi)fallan
- heizan — hiaz — hiazun — (gi)heizan
Consonantal verbs
The origin of the dental suffix is unknown. One theory is that it evolved out of a periphrastic construct with the verb to do, eg I love did > I loved (Germanic *lubōjana dēdo > lubōdo, hence Old English lufode). Another theory is that it came from a past participle ending, a final -daz from IE -tos (cf Latin amatus), with personal endings added to it sometime. Both theories are disputed because of their inability to explain all the facts.
The consonantal preterite, once it formed, became the only productive conjugation in all the Germanic languages. All new verbs in any modern Germanic language are consonantal.
Preterite-presents
Some verbs acquired a present meaning from a perfect form. For example, I have seen came to mean I know. Indo-European *woida, having that meaning (cf Latin vīdi) became Germanic *wait (Gothic wait) with a present meaning. The present tense has the form of a vocalic preterite, with vowel-alternation between singular and plural. The preterite is formed with a dental suffix. Gothic witan:
- witan (infinitive) — wait (1sing, 3sing present) — witun (3pl present) — wista (1sing, 3sing preterite) — witans (past participle)
Further such verbs in Germanic are *kunnana (can, pt kunþa), *unnana (to grant, pt unþa), *gamunnana (to remember, pt gamunda), *dursana (dare, pt dursta), *magana (to be able, may, pt mahta), *skulana (to have to, shall, pt skulda), *þurbana (to need, pt þurfta), *dugana (to avail, pt duhta), *aigana (to have, own, pt aihta) and *mōtana (to be allowed, must, pt mōsta).
Irregular verbs
Some Germanic verbs are truly irregular, having their forms from more than one stem or from an Indo-European paradigm that had normally been lost. For example *wiljana (to want, will) has its present forms from an IE optative. The verb to be has its forms from three IE roots (es-, bhu- and wes-). The verbs to do and to go are also irregular.
