Old english vocabulary

A very short introduction to ablaut The stem vowels ī, ā, i, i shown by rīdan ultimately reflect Indo-European *ei, *oi, *i, *i (giving by regular development Germanic *ī, *ai, *i, *i, giving ultimately Old English ī, ā, i, i). Thus the principal parts in Old English can be explained as reflecting Indo-European *i in combination with either *e (hence *ei), *o (hence *oi), or nothing (hence *i). For these reasons, the infinitive rīdan is said to show the Indo-European e-grade, the past tense singular rād is said to show the Indo-European o-grade, and the past tense plural ridon and past participle (ge)riden are said to show the Indo-European zero-grade, even though, confusingly, the Old English forms themselves do not show e, o, or zero. Similarly bindan ultimately reflects a sequence *en, *on, *n, *n, in which *e, *o, or nothing appear in combination with *n. Similar variation figures largely in a great many etymologies: for some examples see e.g. LOVE n.¹, OWE v., RAW adj. and n.¹, COOL adj., adv., and int., RED adj., n., (and adv.), RIFT n.,
The weak verbs form the past tense and past participle in a quite different way, using a suffix with a vowel followed by -d-, which is the ancestor of the modern inflection in -ed (see ‘-ED’ suffix¹). Thus lufian LOVE v.¹ (a weak Class II verb) shows 1st and 3rd person past singular lufode.
Weak verbs often originated as derivative formations, and often preserve some aspect of this in their meaning, as for example showing causative or inchoative meaning: see below on cēlan ‘to (cause to) cool’ and cōlian ‘to become cool’.
Derivational relationships and sound changes
Many Old English words belong to large groups of words all derived ultimately from the same base, and are related to one another in ways that would have been fairly transparent to speakers of the language. However, in the period of our literary documents the relationships between words were often much less clear than they are likely to have been earlier, because sound changes and other developments had obscured the derivational relationships.
For example, cōl ‘cool’ (see COOL adj., adv., and int.) has a small family of related words in Old English, including cōlnes COOLNESS n., which clearly shows the same base plus ‘-NESS’ suffix. The relationship is similarly clear in the case of the derivative Class II weak verb cōlian ‘to become cool’ (see COOL v.¹).
However, the relationship is less immediately clear in the case of the derivative Class I weak verb cēlan ‘to (cause to) cool’ (see KEEL v.¹). In this case the difference in the stem vowel was caused by an important process called i-mutation which occurred before the date of our earliest records. The earlier form was probably *kōljan. In the process called i-mutation an i or j caused a change in the vowel in the preceding syllable, in this case *ō > *ē. In this word (as in many others) the j was then itself lost, so that by the time of our surviving texts we find cēlan in the same word family as cōl, cōlnes, and cōlian.
The same process explains the variation that we find in the stem vowel in the plural of some words. The word mouse of course shows in modern English the plural form mice; similarly in Old English we find singular mūs but plural mȳs. The earlier forms would have been singular *mūs, plural *mūsi (earlier *mūsiz); i-mutation caused the change *ū > *ȳ in the plural, and then the i was in turn lost, so that in our surviving texts we find singular mūs but plural mȳs.
This and similar processes explain many of the rather complex relationships between related word forms in Old English.