Carpathian ablaut

The Carpathian ablaut (from German Ablaut) is a system of apophony. It is a significant and important part of the Carpathian morphology. The ablaut alternations are grouped into three grades: full, zero and lengthened. The full grade is a short vowel or a diphthong, the zero grade is either a short "i" (rarely also "u") or in some cases no vowel at all, and the lengthened grade is a long vowel. Originally, long diphthongs were a part of the lengthened grade as well, but they merged with their short counterparts everywhere, except under stress. The three grades form a quantitative ablaut type. The other type of ablaut is qualitative and arose from the alternation between original *e and *o in the proto-language, both as monophthongs and diphthongs. Most of the reasons from the rise of ablaut were phonetic, rooted in conditions of stress or in certain phonetic environments. These conditions were later eliminated or altered, resulting in a transformation of ablaut into a morphological change. Analogy and sound changes eliminated most of the inflectional ablaut alternations, thereby simplifying the declensional paradigms and limiting ablaut mostly to derivational morphology. In modern Carpathian, unlike its ancestor Proto-Indo-European, ablaut patterns became etymologically opaque, meaning it is no longer possible to distinguish the original root and from its derivatives. Certain words, created in an ablaut pattern, became obsolescent, leaving gaps in the ablaut chain of their roots. For instance: lōpis “petal” and lapastis “blade” represent lengthened and full grades of the o-vowel. The underlying verb with e-vowel is missing. Very few roots create complete chains with many roots never developing them in the first place, while other roots lost some forms and preserved other, that were used more frequently.

Thus, a complete list of ablaut alternation is represented in the table below:

full	zero	lengthened
e	∅, i, u	e	ē
a		ō
		ā
ai	i	ī
au	u	ū

Some roots exist as doublets — words with similar or identical meaning but different vowel grade. Various dialects preserve different doublets, many of which have a tendency to appear either in Western or Eastern Carpathian exclusively, for example: Western kalaušas — Eastern kilušas “hearing”, beberas “beaver”, kateras “which”, kerna “shrub” — Eastern kilušas, babaras, kataras, kirna.

Lengthened grade

ū- and ī-grades

Unlike in Proto-Indo-European, in Carpathian u and i were full vowels and took part in quantitative alternations alongside o and e. Resulting mostly from the loss of laryngeals "ū" and "ī" gave rise to a lengthened grade, which later spread by analogy and was employed in several morphological categories:

• Forming new intransitive verbs from transitive verbs with full grade vowels: ūktei “to learn”, aukītei “to teach” (full grade), ukinautei “to get accustomed” (zero grade).
• Deriving substantives from verbs with zero grade: źūka “nickname” from źuhētei “to call”, pilīskas “patter” from piliskātei “to clap, to patter”.
• Forming iterative verbs from the non-iterative ones: kalāwītei “to be praising” from kalautei “to be famous”. This type is unproductive and may be a borrowing from the Slavic languages (slaviti from sluti respectively).

ui-grade

The lengthened grade of the u and i vowels arose very early, secured by the loss of laryngeals in that position. The origin of the diphthong ui is more obscure, however. It might have appeared through an analogy with other "i"-type diphthongs ("ai" and "ei") as a full grade of the vowel "u". In the standard "ū" is a lengthened grade and "au" is a full grade instead. A few verbs show this grade in dialects, such as muitei “to wash”, hruitei “to dig” and kiruitei “to cover” (Standard: mautei, hrūtei “to tear out” and karautei respectively).