Reconstruction:Proto-Indo-European/méh₂tēr

Etymology
In older literature usually reconstructed de-laryngealized as and explained as a combination of a nursery word  and the agentive nominal suffix. However, Balto-Slavic forms have acute accent and require a root laryngeal and a short vowel, reflecting *méh₂- (as opposed to *mḗh₂- which would have yielded a circumflexed vowel). Also, no trace of a lengthened grade in the root can be found: in no language did Eichner's law operate (which predicts non-coloration of the *ē in *mḗh₂-tr).

Noun

 * 1)  mother

Reconstruction notes
There is evidence for both suffixal and radical accent: Only one of these can be the original accentuation, which means that the other must have undergone an analogical accent shift. PIE kinship terms that are semantically closest to “mother” are and  and they show in their nominative singular forms accentuation of the suffix, which suggests that the word for “mother” was likely originally accented on the root, shifting its accent to the suffix in some languages under the influence of words for “daughter” and “father”.
 * Germanic  and Sanskrit  show accentuation on the suffix.
 * Greek shows accentuation on the root.
 * Balto-Slavic is inconclusive (the original accent could have been retracted to the root syllable by ).

The reconstruction of the declension paradigm is similarly problematic: From a strictly methodological point of view, this would point to a hysterokinetic inflection, with the reconstructed accusative singular and the genitive singular. However, since the words for “father” and “daughter” appear to have influenced the nominative singular form in some languages, it is possible that the same analogical process occurred in the accusative and genitive singular forms as well.
 * Accusative singular forms are Sanskrit, Ancient Greek , i. e. accented on the suffix only (Lithuanian has radical stress due to ).
 * Genitive singular forms include Sanskrit, Ancient Greek , i. e. accented only on the desinence (Lithuanian has radical stress due to ).

The conclusive evidence for the original acrostatic inflection is the Sanskrit ending for the genitive singular in the word, which is , the same ending used for other kinship terms: , , etc. This ending can only reflect *-C-r-s, with zero-grade of the suffix as well as of the ending, which is only possible in an acrostatic paradigm. A similar ending is found in Old Icelandic, where all kinship terms show the ending -or < PIE *-C-r-s, such as, , ,. However, both in Sanskrit and in Old Icelandic this ending is found in all kinship terms, even in the ones that we know for sure not to have been acrostatically inflected like (genitive  >> Sanskrit, Old Icelandic ) and  (genitive  >> Sanskrit , Old Icelandic ).

It follows that the ending must have spread from some other kinship term. Since PIE must have been acrostatically inflected, the endings  and -or must have been original in this word ( >> Sanskrit, Old Icelandic ). Since it appears unlikely that the ending would have spread so vastly (even to the word for “father”) solely on the basis of the word for “brother”, we must assume that the ending was also present in another kinship term, namely the word for “mother”, which was (as explained above) in its nominative singular form radically stressed, which would fit the acrostatic accentuation pattern, being the source of this genitive singular ending.

Derived terms

 * *meh₂ter-yḗh₂s
 * *meh₂ter-yeh₂
 * *méh₂tr̥-wih₂
 * *meh₂ter-yeh₂
 * *méh₂tr̥-wih₂
 * *méh₂tr̥-wih₂
 * *méh₂tr̥-wih₂

Descendants

 * Armenian:
 * , genitive
 * , genitive