Thematic vowel

In Indo-European studies, a thematic vowel or theme vowel is the vowel or from ablaut placed before the ending of a Proto-Indo-European (PIE) word. Nouns, adjectives, and verbs in the Indo-European languages with this vowel are thematic, and those without it are athematic. Used more generally, a thematic vowel is any vowel found at the end of the stem of a word. Outside Indo-European, the term "thematic vowel" is also used in the grammar of Kartvelian languages (see Georgian verb paradigm for more information on thematic vowels). PIE verbs and nominals (nouns and adjectives) consist of three parts: The thematic vowel, if present, occurs at the end of the suffix (which may include other vowels or consonants) and before the ending: 'heat' > Ancient Greek θέρμος (thérmos) '(he) bears' > Sanskrit bhárati, Gothic baíriþ Athematic forms, by contrast, have a suffix ending in a consonant, or no suffix at all (or arguably a null suffix): 'father' > English father '(I) am' > English am For several reasons, athematic forms are thought to be older, and the thematic vowel was likely an innovation of late PIE: Athematic paradigms (inflection patterns) are more "irregular", exhibiting ablaut and mobile accent, while the thematic paradigms can be seen as a simplification or regularisation of verbal and nominal grammar. In the Anatolian languages, which were the earliest to split from PIE, thematic verbs are rare or absent. Furthermore, during late PIE and in the older daughter languages, a number of athematic forms were replaced by thematic ones, as in prehistoric Greek *thes- 'god' versus *thes-o- > Classical Greek θεός (theós). The thematic vowel technically belongs to the suffix and not the ending, as each suffix is inherently either thematic or athematic. It is also used in some cases to derive stems from roots directly, acting as a suffix in itself (as in the second example above). However, when considering endings which are different for thematic and athematic inflections, it is generally included in the endings as well; see the section on fusion below.