Indo-European Ablaut - Subsequent Development

Subsequent Development

Although PIE only had this one, basically regular ablaut sequence, the development in the daughter languages is frequently far more complicated, and few reflect the original system as neatly as Greek. Various factors such as vowel harmony, assimilation with nasals, or the effect of the presence of laryngeals in the Indo-European (IE) roots and their subsequent loss in most daughter languages, mean that a language may have several different vowels representing a single vowel in the parent language. Thus while ablaut survives in some form in all Indo-European languages, it becomes progressively less systematic over time.

Ablaut explains vowel differences between related words of the same language. For example:

• English fetch and foot both come from the same IE root *ped-, the common idea being "going". The former comes from the e-grade, the latter from the lengthened o-grade.
• German Berg (hill) and Burg (castle) both come from the root *bʰergʰ-, which presumably meant "high". The former comes from the e-grade, the latter from the zero-grade. (Zero-grade followed by r becomes ur in Germanic.)

Ablaut also explains vowel differences between cognates in different languages.

• English tooth comes from Germanic *tanþ-s (e.g. Old English tōþ, Old High German zand), genitive *tund-iz (Gothic tunþus, but also aiƕa-tundi "thornbush", literally "horse-tooth"). This form is related to Latin dens, dentis and Greek ὀδούς, ὀδόντος (same meaning), reflected in the English words dentist and orthodontic. One reconstructed IE form is *dónts, genitive *dn̥tés. The consonant differences can be explained by regular sound shifts in primitive Germanic, but not the vowel differences: by the regular laws of sound changes, Germanic a can originate from PIE o, but un usually goes back to a syllabic n̥. The explanation is that the Germanic and Greek nominative forms developed from the o-grade, the Latin word and the Germanic genitive from the zero-grade (where syllabic n̥ developed into en much in the same way as it became un in Germanic). Going a step further back, some scholars reconstruct *h₁dónts, from the zero grade of the root *h₁ed- 'to eat' and the participal -ont-, so explaining it as 'the eating one'.
• English foot, as mentioned above, comes from the lengthened o-grade of *ped-. Greek πούς, ποδός and Latin pes, pedis (cf. English octopus and pedestrian), come from the (short) o-grade and the e-grade respectively.

For the English-speaking non-specialist, a good reference work for quick information on IE roots, including the difference of ablaut grade behind related lexemes, is Calvert Watkins, The American Heritage Dictionary of Indo-European Roots, 2nd edition, Boston & New York 2000.

(Note that in discussions of lexis, IE roots are normally cited in the e-grade and without any inflections.)