The whole earth
'erets  (eh'-rets)
the earth (at large, or partitively a land) -- common, country, earth, field, ground, land, natins, way, + wilderness, world.
is at rest
nuwach  (noo'-akh)
to rest, i.e. settle down; used in a great variety of applications
and is quiet
shaqat  (shaw-kat')
to repose (usually figurative) -- appease, idleness, (at, be at, be in, give) quiet(-ness), (be at, be in, give, have, take) rest, settle, be still.
they break forth
patsach  (paw-tsakh')
to break out (in joyful sound) -- break (forth, forth into joy), make a loud noise.
into singing
rinnah  (rin-naw')
a creaking (or shrill sound), i.e. shout (of joy or grief) -- cry, gladness, joy, proclamation, rejoicing, shouting, sing(-ing), triumph.