Proto-Indo-European *a

There are around sixty Indo-European roots that are (sometimes) reconstructed with a vowel *a in the scholarly literature that otherwise fully embraces the laryngeal theory. This number is extremely low compared to the number of morphemes in which the vowels that are traditionally reconstructed as *e and *o are found. This marginal status of the vowel *a is typologically odd and has led some scholars to deny the existence of a vowel *a in Proto-Indo-European or in a precursor of Proto-Indo-European. This paper discusses the comparative evidence for the reconstruction of Proto-Indo-European *a. It concludes that there is insufficient evidence for the reconstruction of *a for any stage of the proto-language.