A small number of Old Aramaic words attest a spelling of the inherited "feminine" suffixes as -t. Strikingly, all of these words occur in syntactic contexts where Proto-Semitic would use the accusative case. Wherever the nominative or genitive case is expected instead, the "feminine" suffix is not spelled with -t. This includes several forms that are here argued to showcase a development of the "feminine" plural ending *-āt- into *-ā, spelled -h in the Sefire inscriptions and left unspelled in the Tell Fekheriye inscription. This identification of-h and zero as spelling the "feminine" plural suffix provides us with enough evidence to establish the syntactic conditioning of-t in accusative contexts vs.-h or zero in other contexts. The retention of t in the accusative follows naturally from the longer retention of word-final *-a in Proto-Aramaic compared to *-u and *-i, which is supported by morphological developments in the verb. Together with the plene spelling of the "masculine" plural ending as -wn in nominative contexts and as -yn elsewhere in the Tell Fekheriye inscription, the identification of a separate accusative form of the "feminine" suffixes shows that Old Aramaic retained a partial contrast between the three Proto-Semitic cases. Later on, this case distinction was lost, while accusative forms in -t became lexicalized adverbs.