Axel,
Just to nit-pick, AFAIK, there is no original Aramaic text. The oldest written record is Greek–the Gospels of Matthew, Mark, Luke, and John which were written about 30-50 AD (that’s “after death,” not Anno Domini) :). That still doesn’t answer the question of whether the Aramaic word for “lake” and “feed trough” are similar, but “feed trough” fits more in line with the stable setting.
BTW, “manger” is mentioned only in the book of Luke.