DICTIONARY OF REVIVED PRUSSIAN:

(West Baltic) as well as in Slavic (one should expect “instr.” o menim, not o manim).
In Old Prussian the instrumental meaning is expressed by means of the preposition
sen + either the accusative form (the new development), or the dative form (archaic
senpackai ‘sicher’ III, as in German or in Greek). Since the expression As N. imma
tin N. m`im prei ainan Salûbin ‘Ich N. neme dich N. mir zu einem Ehelichen Gemahel’
III undoubtedly demonstrates the dative, not instrumental ( o manim), meaning, one
may consider m`im to be dative/ accusative, probably an archaic enclitic m`i (in
Pomezanian – *môi due to the circumflex, cf. Grunau’s Dam thoi ‘I am giving to
you’), dativized with the formant -m. 12
Some “Lithuanisers” also used to negate the original nature of the Prussian astem
gen. sg. masc. -as, saying it was a German generalization of the gen. sg. -s and
pointing to an ostensibly preserved gen. butta tawas (beside buttastaws) ‘house father,
master’ III = Lith. gen. (but)o. Authentic instances of compounds with the genitive
in the first component, such as silkasdrûb’ E 484 [silkasdrimbis] ‘silk cover’ or
topon. Wilkaskaymen ‘Wolf’s village’, render any Lithuanisation senseless.
8. Systemzwang
This German term means a paradigmatic constraint under which phonetic rules do
not operate if they resulted in changing the standard appearance of the paradigm. In
Samlandian, the long vowels *`, *ô turn into *û after labial and guttural consonants.
In many case-forms e.g. nom. sg. fem. -a < *-` is reprersented as (-u