Indo-European Ablaut - Grammatical Function

Grammatical Function

In PIE, there were already ablaut differences within the paradigms of verbs and nouns. These were not the main markers of grammatical form, since the inflection system served this purpose, but they must have been significant secondary markers.

An example of ablaut in the paradigm of the noun in PIE can be found in *pértus, from which the English words ford and (via Latin) port are derived (both via the zero-grade stem *pr̥t-).

		root (p-r)	suffix (t-u)
Nominative	*pér-tu-s	e-grade	zero-grade
Accusative	*pér-tu-m	e-grade	zero-grade
Genitive	*pr̥-téw-s	zero-grade	e-grade
Dative	*pr̥-téw-ey	zero-grade	e-grade

An example in a verb: *bʰeydʰ- "to wait" (cf. "bide").

		e-grade
Perfect (3rd singular)	*bʰe-bʰóydʰ-e	o-grade	(note reduplicating prefix)
Perfect (3rd plural)	*bʰe-bʰidʰ-ḗr	zero-grade	(note reduplicating prefix)

In the daughter languages, these came to be important markers of grammatical distinctions. The vowel change in the Germanic strong verb, for example, is the direct descendant of that seen in the Indo-European verb paradigm. Examples in modern English are:

Infinitive	Preterite	Past participle
sing	sang	sung
give	gave	given
strive	strove	striven
break	broke	broken

It was in this context of Germanic verbs that ablaut was first described, and this is still what most people primarily associate with the phenomenon. A fuller description of ablaut operating in English, German and Dutch verbs and of the historical factors governing these can be found at the article Germanic strong verb.

The same phenomenon is displayed in the verb tables of Latin, Ancient Greek and Sanskrit. Examples of ablaut as a grammatical marker in Latin are the vowel changes in the perfect stem of verbs.

Present tense	Perfect
agō	ēgī	"to do"
videō	vīdī	"to see"	(vowel lengthening)
sedeō	sēdī	"to sit"	(vowel lengthening)
cadō	cecidī	"to fall"	(note reduplicating prefix)

Ablaut can often explain apparently random irregularities. For example, the verb "to be" in Latin has the forms est (he is) and sunt (they are). The equivalent forms in German are very similar: ist and sind. The same forms are present in Slavic languages – est and sut' . The difference between singular and plural in these languages is easily explained: the PIE root is *h₁es-. In the singular, the stem is stressed, so it remains in the e-grade, and it takes the inflection -ti. In the plural, however, the inflection -énti was stressed, causing the stem to reduce to the zero grade: *h₁es-énti → *h₁s-énti. See main article: Indo-European copula.

Some of the morphological functions of the various grades are as follows:

e-grade:

• Present tense of thematic verbs; root stress.
• Present singular of athematic verbs; root stress.
• Accusative and vocative singular, nominative/accusative/vocative dual, nominative plural of nouns.

o-grade:

• Verbal nouns — (1) stem-stressed masculine action nouns (Greek gónos "offspring", Sanskrit jánas "creature, person"; Greek trókhos "circular course" < "*act of running"); (2) ending-stressed feminine, originally collective, action nouns (Greek gonḗ "offspring", Sanskrit janā́ "birth"); (3) ending-stressed masculine agent nouns (Greek trokhós "wheel" < "*runner").
• Nominative/vocative/accusative singular of certain nouns (acrostatic root nouns such dṓm, plural dómes "house"; proterokinetic neuter nouns such as *wódr̥ "water" or dóru "tree").
• Present tense of causative verbs; stem (not root) stress.
• Perfect singular tense.

zero-grade:

• Present dual and plural tense of athematic verbs; ending stress.
• Perfect dual and plural tense; ending stress.
• Past participles; ending stress.
• Some verbs in the aorist (the Greek thematic "second aorist").
• Oblique singular/dual/plural, accusative plural of nouns.

lengthened grade:

• Nominative singular of many nouns.
• Present singular of certain athematic verbs (so-called Narten-stem verbs).
• Some verbs in the aorist.
• Some derived verbal nouns (so-called proto-vrddhi).

Note that many examples of lengthened-grade roots in daughter languages are actually due to the effect of laryngeals, and of Szemerényi's law and Stang's law which operated within Indo-European times.