Ablaut

Ablaut is an element of all the source languages; an English example is song sing sang sung.

Ablaut is the phenomenon wherein stem vowels change form depending on context, as in English sing, sang, sung.

A few verbs have palatalization in the active along with s in the 3rd singular, but no palatalization and no s in the mediopassive, along with no root ablaut (the vowel reflects PToch ë).

Both root and suffix ablaut is still well-represented, although again with significant innovations.

Frequently mentioned is Esperanto's agglutinative morphology based on invariant morphemes, and the subsequent lack of ablaut (internal inflection of its roots ), which Zamenhof himself thought would prove alien to non-Indo-European language speakers.

However, the majority of words in all Indo-European languages inflect without ablaut, as cat, cats and walk, walked do in English.

In addition, four subjunctive classes differ from the corresponding indicative classes, two "special subjunctive" classes with differing suffixes and two "varying subjunctive" classes with root ablaut reflecting the PIE perfect.

In addition, nouns of e-stems have an ablaut of long vowel ė in nominative and short vowel e /ɛ/ in vocative.

In the first three pairs of vowels, Bomhard is attempting to specify the subphonemic variation involved, inasmuch as that variation led to some of the vowel gradation ( ablaut ) and vowel harmony patterning found in various daughter languages.

Morphological effects Although umlaut was not a grammatical process, umlauted vowels often serve to distinguish grammatical forms (and thus show similarities to ablaut when viewed synchronically), as can be seen in the English word man.

Root ablaut occurs between active and mediopassive.

Some verbs are derived by ablaut, as the present-in-past verbs do by consequence of being derived from the past tense forms of strong verbs.

There is no ablaut in this class.

This class shows root ablaut, with original e-grade (and palatalization of the initial root consonant) in the active singular, contrasting with zero-grade (and no palatalization) elsewhere.

Varying subjunctives: *i: Athematic without suffix, with root ablaut reflecting PIE o-grade in active singular, zero-grade elsewhere.