The suffix used for the draft-instrumental case, translated “with” (SD/438). In a later conceptual stage, it became the ordinary prepositional suffix -mâ. Carl Hostetter and Partick Wynne suggested (VSH/33, AAD/19) that the deleted form -men on SD/311 is a separate prepositional suffix “on” related to ᴹQ. men “place”, but I believe it is a variant of the plural instrumental form -main.
-masuffix. instrumental (draft), with