The inflection of the verb in the Germanic languages is much simpler than it was in Indo-European times. A comparison of the Old English verb with the verbal inflection of Greek or Latin will show how much has been lost. Old English distinguished only two simple tenses by inflection, a present and a past, and except for one word, it had no inflectional forms for the passive as in Latin or Greek. It recognized the indicative, subjunctive, and imperative moods and had the usual two numbers and three persons.
A peculiar feature of the Germanic languages was the division of the verb into two great classes, the weak and the strong, often known in Modern English as regular and irregular verbs. These terms, which are so commonly employed in modern grammars, are rather unfortunate because they suggest an irregularity in the strong verbs that is more apparent than real. The strong verbs, like sing, sang, sung, which represent the basic Indo-European type, are so called because they have the power of indicating change of tense by a modification of their root vowel. In the weak verbs, such as walk, walked, walked, this change is effected by the addition of a “dental”, sometimes of an extra syllable.
The apparent irregularity of the strong verbs is due to the fact that verbs of this type are much less numerous than weak verbs. In Old English, if we exclude compounds, there were only a few over 300 of them, and even this small number falls into several classes. Within these classes, however, a perfectly regular sequence can be observed in the vowel changes of the root. Nowadays these verbs, generally speaking, have different vowels in the present tense, the past tense, and the past participle. In some verbs the vowels of the past tense and past participle are identical, as in break, broke, broken, and in some all three forms have become alike in modern times (bid, bid, bid). In Old English the vowel of the past tense often differs in the singular and the plural; or, to be more accurate, the first and third person singular have one vowel while the second person singular and all persons of the plural have another. In the principle parts of Old English strong verbs, therefore, we have four forms: the infinitive, the preterite singular (first and third person), the preterite plural, and the past participle. In Old English the strong verbs can be grouped in seven general classes. While there are variations within each class, they may be illustrated by the following seven verbs:
The origin of the dental suffixes by which weak verbs form their past tense and past participle is strongly debated. It was formerly customary to explain these as part of the verb do, as though I worked was originally I work – did (i.e., I did work). More recently an attempt has been made to trace these forms to a type of verb that formed its stem by adding -to- to the root. Here it is sufficient to note that a large and important group of verbs in Old English form their past tense by adding –ede, –ode, or –de to the present stem, and their past participles by adding –ed, –od, or –d. Thus fremman (to perform) has a preterite fremede and a past participle gefremed; lufian (to love) has lufode and gelufod. It is to be noted, however, that the weak conjugation has come to be the dominant one in the English language. Many strong verbs have passed over to this conjugation, and practically all new verbs added to English are inflected in accordance with it.