Reconstruction:Proto-Celtic/essi

Etymology
Virtually everyone agrees that this verb came from. However, the present stem of this verb is one of the most controversial to reconstruct in Proto-Celtic, only matched in controversy with the preterite of. There are two major theories on how the Goidelic present stem ith- came to be, all of them attributing it to an analogical reformation based on the root *ɸit- that is present in the verbal noun in addition to. The steps leading to the suppletion remain up for debate.


 * McCone and the KPV reconstruct an original athematic, leading to Celtic *īd- in the singular and *ed- in the plural. They then have the ablaut reshaped to respectively *īd- and *id- and then harmonized to *id- for both singular and plural. Then, after the loss of initial ɸ in Insular Celtic, stem id- was replaced with it- and thematised.
 * Lindeman and Sandell, finding no other secure Indo-European evidence of a Narten present formation for this verb, independently prefer a simple direct derivation from the e/zero-grade athematic, which would lead to an extremely anomalous Proto-Celtic paradigm *edmi, *essi, *essi, etc. which was ripe for replacement by a simpler suppletive formation. After a further thematicisation to *esseti, Lindeman and Sandell posit different motivations for the later suppletion.
 * Lindeman thought that the suppletion was caused by the newly thematic present being identical with its own subjunctive, with a new present stem that was very distinct from the subjunctive stem being desired.
 * Sandell instead draws on the verbal noun itself as the trigger for analogy. He notes that many Old Irish verbal nouns in -e (from Proto-Celtic ) correspond to B I (and some B II) verbs with transparent relationships between the present stem and the verbal noun. The lack of transparency between the original present stem and the verbal noun  in Old Irish led to remodeling with a present stem ith- to match.
 * Matasović attempts to substitute KPV and McCone's Narten present with an i-reduplicated -style present. Sandell dismisses Matasović's derivation for lacking a subsequent mechanism to reach a short i- stage from the resulting *īdeti.
 * Matasović's derivation can be salvaged by assuming that itself intervened to force a short i. Influence of  is not unparalleled, as KPV attributes 's a-future to analogy with, which descends from  and also has an a-future (although  also acquired its a-future secondarily).

Verb

 * 1) to eat