Appendix:Old High German verbs

Strong verbs
Strong verbs are verbs that form their preterite tense by ablaut, or changing the vowel of the stem. In some words, the vowel of the present singular indicative forms is different from the infinitive and other present forms, due to earlier i-mutation.

Weak verbs
Weak verbs are verbs that form their preterite tense by adding -t-.

Class 1
In class 1 weak verbs, the infinitive ends in -en, but also sometimes -an under influence of the strong infinitive. Verbs with a stem in -r- usually have -ien. Class 1 weak verbs can be divided into three types based on the length of the stem.

Geminated stems
Verbs in this subgroup are the ones affected by the West Germanic gemination. These verbs have a stem with a short vowel followed by a geminated consonant (except pf, zz or hh). Not all verbs with a stem ending in a double consonant belong to this subgroup, as the gemination may also have been inherited from Proto-Germanic (e.g. kennen).

The gemination affects all present tense forms except the 2nd and 3rd person singular indicative and the 2nd person singular imperative. It does not affect the past tense at all, which has a single consonant followed by -it-. Verbs whose stems end in -tt- or -ll- sometimes have preterites as the heavy stems, e.g. zellen appears as either zelita or zalta.

Heavy stems
Verbs in this subgroup were not affected by the West Germanic gemination, and have a stem ending in two consonants or have a long vowel or diphthong. Verbs with stems ending in -pf-, -zz- or -hh- which developed through the High German consonant shift also belong to this group. Verbs that end in a double consonant as a result of the West Germanic gemination belong to the geminated verbs instead.

The past tense has -t- attached directly to the stem with no intervening vowel. This will cause geminate consonants to simplify, as long consonants cannot occur in a consonant cluster; e.g. -nn- + -t- becomes -nt-, and -nt- + -t- remains -nt-. The absence of the intervening vowel prevents the application of umlaut of the stem in the past tense. Thus, present e alternates with past a (the Rückumlaut phenomenon), e.g. brennen > branta and irkennen > irkanta.

r-stems
Verbs in this subgroup have a short vowel followed by -r-. The consonant r was not affected by the gemination, keeping the stem light in all the forms. The lack of gemination allowed the original inflectional -j- that was present in Proto-Germanic to remain, and it is found before most of the endings in the present tense, spelled as -i-. For example, the infinitive ending is -ien. The past tense is formed like the geminated stems, with -it-.

Some verbs of this type have later developed gemination by analogy, so -rren can also be found alongside -rien.

Class 2
Class 2 weak verbs have infinitives in -on, while endings contain an -o- which was long in earlier Old High German. The preterite is formed by adding -ot-.

Class 3
Class 3 weak verbs have infinitives in -en, while endings contain an -e- which was long in earlier Old High German. The preterite is formed by adding -et-.

Preterite-present verbs
Preterite-present verbs are verbs that form their present tense with the strong preterite. Their preterite tense is then formed with the weak dental preterite.

These verbs usually serve an important grammatical role as modal verbs or auxiliary verbs.