Though the name is from Sweden the language is Greek. This is a snob thing, educated people used to adopt Latin or Greek versions of their names in some European countries. Surnames ending in -mann often became xxxander, from the Greek word for man (root, andr). So you have surnames such as Orander for Bergmann, Neander for Neumann or Nymann, Xylander for Holzmann, etc. My knowledge of Greek is limited to virtually nil, so I can't help you with the LEK component. I should state that it should be classical, rather than Modern Greek. Also it's possible that it isn't Greek at all. Some snobs were not so clever, and combined Latin and Greek, e.g., Taxiander; and some just translated half of the name, e.g., one smartypants named Hosemann who became Osiander.