By mundialecter
In Sambahsa, "each other" is mutu, 'mutu. "Along, on the edge of" is ana, 'ana, and "sea" is mar, mar. "With", when it refers to an idea of "com-pany", is con, kon.
Translate now : "They walk with each other along the sea.", with no personal pronoun, but with the long ending of the 3° person plural.