Hellene and Greece ,levelling the words

Selenje or Migration -explanation of:

Migrātiō, ōnis f removal, migration; change of meaning.
Migrō 1 a) to remove, depart, emigrate (ab, ex, de re in or ad alqd);
b) trans. to transport; to transgress.

Ref: S.A. Handford and Mary Herberg “Latin-English, English -Latin dictionary” Germany 1955, 1966.Berlin and Munich … p.200

migrant n 1. a person or animal that moves from one region, place or country to another .
2. an itinerant agricultural worker. ~ adj.
3. moving from one region, place or country to another; migratory.
migrate vb.(intr.) 1. to go from one place to settle in another, esp. in a foreign country.
2.(of birds, fishes, etc.) to journey between different habitats at specific times of the year.[C17: < L migrare to change one’s adobe] –mi’grator n.
migration n. 1.the act or an instance of migrating. 2. a group of people, birds, etc. migrating in a body.
3. Chem. a movement of atoms, ions, or molecules, such as motions of ions in solution under the influence of electric fields. –mi’grational adj.
migratory adj.1. of or characterized by migration. 2. nomadic; itinerant

Ref. “The new Collins concise dictionary of the English language”. London & Glasgow 1987…p.714-715
Standard ISBN 0 00 433091-9
Indexed ISBN 0 00 433070-6

Ok but in which language "S" was changed to "H", Selen -> Helen?

Sindh -> Hind (India), Asura -> Ahura, Soma -> Haoma, ...

And to be more official with some credible source, read this:

http://www.etymonline.com/index.php?term=Greek