Etruscan such and such

There's a curious lexeme with an interesting inflection in the Liber Linteus (LL 6.xviii): caticaθ. Another similar form is found again at LL 7.xix but this time as cnticnθ. Are they related and if so how? What is the origin?

Contextually it appears that an English equivalent like this very (one) is a nice fit, or alternatively such. The word might then be compared to the semantics of Latin talis 'such, such like, the like'. It preposes the noun it modifies as is seen in caticaθ luθ. Since nominative ca 'this' and its accusative can ~ cn is so well attested, it makes sense that we should trace both caticaθ and cnticnθ to the respective case forms of their simple demonstrative counterparts.

But what is going on with these forms? Why, in a language that agglutinates with suffixes, are there internal case changes in this form? My solution is that caticaθ stems from a reduplicated earlier form *kati-kati (in the Proto-Cyprian stage), itself built on the form *ka-ti 'like this'. The corresponding accusative form at this stage would be *kanti-kanti which over time is reduced to cnticnθ. The source of this alternation is thus easily obscured.

I propose that this postposition -ti 'like, as', which is not to be confused with -θi 'in' pronounced with an aspirated plosive, is also found in clanti 'stepson, adopted son' (literally 'like a son; son-like') paralleling in meaning and form the Latin term fīliaster 'stepson' (< fīlius 'son' plus derivational suffix -aster).