|Function:||dat. sg. (on-stem)|
|Attestation:||)kionei, atilonei, piuonei|
Cisalpine Celtic documents the retention of the original dative ending -ei̯ in on-stems, which has been replaced by the locative singular ending -i in Transalpine Gaulish and Old Irish, and is also attested in Cisalpine Celtic (see -oni) (Eska & Wallace 2001, Eska 2009: 23, Eska & Evans 2009: 36). The rationale of the chronological and linguistical mapping of the two endings in the Cisaline Celtic evidence is not quite clear yet.
|Eska & Evans 2009||Joseph Francis Eska, David Ellis Evans, "Continental Celtic", in: Martin J. Ball, Nicole Müller (eds), The Celtic Languages, 2nd edition, London – New York: Routledge 2009.|
|Eska & Wallace 2001||Joseph F. Eska, Rex E. Wallace, "A syncretism in fieri in early Celtic", Indogermanische Forschungen 106 (2001), 229–240.|
|Eska 2009||Joseph Francis Eska, "The emergence of the Celtic languages", in: Martin J. Ball, Nicole Müller (eds), The Celtic Languages, 2nd edition, London – New York: Routledge 2009, 22–27.|