Proto-Indo-European Lexicon (PIE Lexicon) is a generative etymological dictionary of Indo-European languages. PIE Lexicon is an academic open source database published online at the address http://pielexicon.hum.helsinki.fi.
PIE Lexicon is an etymological dictionary that will comprise the main bulk of the vocabulary of more than one hundred of the most ancient Indo-European languages when the first phase of the project has been accomplished. When ready, the project will expand to its second phase in which the later Indo-European languages will be added to the database.
The next-generation feature of the dictionary is the automatic generation of the Indo-European data, quoted in a stem form (i.e. without inflectional endings), on the basis of the digitised Indo-European sound laws and a primary phoneme inventory postulated for the Proto-Indo-European language. This stage will formalize the prediction of descendant forms from reconstructed Proto-Indo-European forms.
The background of Proto-Indo-European Lexicon is Jouna Pyysalo‘s dissertation (2013): System PIE: The Primary Phoneme Inventory and Sound Law System for Proto-Indo-European. In this monography Pyysalo presents the solution to the Proto-Indo-European laryngeal problem and the primary phoneme inventory for Proto-Indo-European. In the chapters dealing with functionally defined classes of phonemes he thoroughly revises, corrects and finally completes the Indo-European sound laws into a system consistent internally and with the data.
Pyysalo's work is committed to the method of natural science, a suitable choice as the comparative method of reconstruction in Indo-European linguistics is presented as a branch of natural science within humanities.
The significance of the solution to the PIE laryngeal problem lies in the fact that the "laryngeal" is the last uninterpreted piece of the PIE phoneme inventory. With the missing link of the PIE sound system at his disposal, Pyysalo segmentally analyses the traditionally postulated proto-phonemes of the historical theories and comparatively infers a minimal set of phonemes for the PIE consisting of twenty-eight paired segments:
Length, syllabicity and voicing and contrasts are claimed to be allophonic, which would leave an inventory of fourteen phonemes.
The solution to the Proto-Indo-European laryngeal problem, viz. the question of the phonetic interpretation and the number of "laryngeals" of the proto-language has been disputed ever since Bedřich Hrozný's demonstration of the Indo-European character of the Hittite language. Pyysalo 2013 proposes an inductive solution to the problem, according to which:
- Proto-Indo-European had a single "laryngeal", reconstructed as a glottal fricative with voiceless and voiced variants *[h] and *[ɦ], both segmentally preserved in Hittite ḫ.
- Proto-Indo-European *h/ɦ was always accompanied by PIE *ɑ (the reinterpreted Schwa Indogermanicum) thus appearing in the diphonemic pairs PIE *hɑ *ɑh *ɦɑ *ɑɦ.
The digitalisation of Pyysalo 2013 has been ongoing since June 2014 in the PIE Lexicon address http://pielexicon.hum.helsinki.fi with a straightforward goal of implementation of the data and the sound laws into a platform using finite state technology (Foma application), thus effectively upgrading the earlier System PIE into an Operating System (OS) PIE Lexicon, the next-generation etymological dictionary of Indo-European languages.
The key difference of between the PIE Lexicon and all its predecessors (including Pokorny and LIV2, etc.) is not as much the digital platform but the digitalised, chronologically arranged sound law (or Foma-)scripts written for each language presented in PIE Lexicon. By means of the Foma-scripts the OS PIE Lexicon automatically (re-)generates the Indo-European words exactly as they were once born from Proto-Indo-European.
Historically PIE Lexicon continues the comparative tradition of Indo-European linguistics, which is often contrasted to the laryngeal theory, attempting to offer a more regular account of PIE ablaut.
Despite this a straightforward opposition of the two views is, however, less recommendable: Rather than standing in opposition to the laryngeal theory the System PIE (and OS PIE Lexicon) can be characterised as containing elements from all historical mainstream schools of thought, i.e. from the Paleogrammarians, the Neogrammarians, the laryngeal theory and monolaryngealism.
Thus, for instance, the solution to the laryngeal problem, PIE *hɑ *ɑh *ɦɑ *ɑɦ, contains PIE *ɑ, the former Schwa Indogermanicum inherited from the Neogrammarians, the single laryngeal from monolaryngealism, but also accepts the colouring rules of the laryngeal theory, thus e.g. deriving the vowel Neogr. *a from PIE *ɑe (cf. Møller's Ae -> a) and so forth.
Hitherto the main problem (and criticism) of the theory is the lack of typological parallel for the existence of diphonemic PIE *hɑ *ɑh *ɦɑ *ɑɦ in the languages of the world, as already mentioned in Pyysalo 2013 (461-2): Although already the Neogrammarians proved the existence of the vowel *ǝ (reinterpreted as PIE *ɑ in System PIE) and the Anatolian data preserves a single laryngeal Hittite ḫ, "It is desirable that a typological parallel be found for a system of phonemes PIE *ɑ and PIE *ḫ choosing each other (strict phonotactical selection) in diphonemic PIE *ɑḫ : ḫɑ (...)”