Darnassian
Darnassian is the primary language of night elves. It has both written and spoken equivalents.

Just as the naga, high elves, and blood elves are descended from night elves, so Darnassian bears some resemblance to the Nazja and Thalassian languages. There are, however, strong ideological differences between the night elves and their distant kin. Thus, a linguist must take great care in drawing comparisons between Darnassian and its two cousin languages. Night elves tend to consider such comparisons offensive.

Darnassian Translation Usage and Context
Ande'thoras-ethil. May your troubles be diminished. A farewell.
Andu-falah-dor! Let balance be restored! A war cry that came into popular use only after the Great Sundering, when the night elves resolved to protect the balance of nature.
Ash karath! Do it! Just as in Common, this command is a relatively generic one and can be used in multiple contexts. The speaker is telling someone to carry out an implicit action.
Bandu thoribas! Prepare to fight! A challenge to battle that has been used against enemies since ancient times.
Elune-adore. Elune be with you. A greeting that is frequently used among the Sisters of Elune. It is also used from time to time by most night elves.
Fandu-dath-belore? Who goes there? A call to an unknown party for identification. Used exclusively in military situations.
Ishnu-alah. Good fortune to you. A common greeting.
Ishnu-dal-dieb. Good fortune to your family. A common greeting.
kaldorei children of the stars Can also be interpreted as "people of the stars". Typically used to refer to night elves.
nordrassil crown of the heavens When used as a proper noun, Nordrassil refers to the first World Tree.
quel'dorei children of noble birth This term once referred to the highest caste of night elf society in ancient times, the Highborne, who have largely been slain or transformed. Today this term is typically used to refer to the high elves.
shan'do honored teacher A courtesy title of great respect.
sunstrider he who walks the day When used as a proper noun, Sunstrider is the surname of an ancient Highborne family. The Sunstrider family later became the high elves' royal bloodline, the last scion of which is Prince Kael'thas Sunstrider.
teldrassil crown of the earth When used as a proper noun, Teldrassil refers to the second World Tree.
thero'shan honored student A courtesy title of great respect.
Tor ilisar'thera'nal! Let our enemies beware! A war cry used against enemies since ancient times.
xaxas elemental fury This term has many alternative interpretations, including "chaos" and "catastrophe". When used as a proper noun, Xaxas refers to Deathwing.
zin-Azshari the glory of Azshara When used as a proper noun, Zin-Azshari refers to the capital city of night elf society during Queen Azshara's reign.