In a land guarded by magic hid a group of Telerin Elves. They were called the Sindar, the Grey Elves. It was in that land, named Doriath, that a unique Elven language was born: Doriathrin, the predecessor to Sindarin.

The Sindar prospered for many ages in the dark, but then the dawn came. Following the sun on its eastbound trail, the Kinslaying Noldor, who were banished from Aman for murdering the peaceful Telerin Elves of Alqualondë, came to Doriath. When the King discovered the crimes of the Noldor against his kin, he forbade the use of the Noldorin language: Quenya. He ordered all peoples in his kingdom to shun those who spoke Quenya openly. The Noldor were forced to learn Doriathrin.

When foreign tongues pronounce words new to them, they change the words a little. Doriathrin was changed by the Noldorin tongues into a new dialect, which I will call Noldorin-Sindarin.

Then Doriath fell into ruin. Almost all of the Noldorin strongholds in Middle-earth fell as well, sending the Elves fleeing further from Aman, deeper into Middle-earth. With the help of Men, Melkor, the one who had been making all of these strongholds fall, was cast into the void for all eternity. The Noldor eventually settled to wait out their banishment in Eriador.

The Sindar fled all the way to their Telerin cousins on either side of the Misty Mountains: the Dannas, or Nandor. With them they brought their language, and the Dannas adopted it like they adopted their Telerin kin into their forests. They changed the language slightly again, but adding not much more than a thick accent and making the diphthong AE to E in names. This I will call the Nandorin-Sindarin.

Then the Men living in Númenor, given the island for helping rid Arda of Melkor, who had also adopted Sindarin into their daily lives, were cast out of Númenor for trying to become immortal. They had their own language: Adûnaic, or Westron. The descendant of their language would become the Common Tongue of Middle-earth. When they adopted Sindarin, they added their own slant to it, making Gondorian-Sindarin.

And here we are at the beginning of the Third Age of Middle-earth, with three dialects to choose from. This textbook covers the Gondorian and Noldorin dialects of Sindarin. The Nandorin dialect of Sindarin we know very little about, except that they had a heavy accent, that Galadriel, a Noldo, didn't have too hard a time understanding them, and that the E in "Legolas" comes from the diphthong AE. Studying the Gondorian and Noldorin dialects is the best way to go about this, and I will take care to mention the differences between them as we go along.

Ist valan! Knowledge is power!