The Sylvan language is a hybrid of Quenya (the preferred language of the Ents (other then entish which is undocumented)) and Black Speech/Koboblah. Essentially "c"'s in Quenya are usually pronounced as "k"'s so any "c"'s have been changed to "k"s. The number system is the same as the kobold one, only elongating the vowels. The Sylvans acknowledge standard Quenya as their "Ancient Sylvan" and the new language as their common tongue. Common is used almost exclusively, though their may be Sylvan ceremonies and such that will dig deeper into the ancient language.

A few Quenya language sites:
Quenya Corpus Wordlist (most commonly used list)
English to Quenya
Quenya to English
A Quenya Course (more than a member is expected to learn/use, provided for reference).

In an effort to tie back into Entish and a way to easily delineate which race is talking, sentences use dashes (-) instead of spaces.
e.g.:
human: Lets go kill stuff.
kobo: Litz gu klomp stuv.
sylvan: Let-nia-goo-upruut-stuuf.

As far as speech patterns for non specific words, the Sylvans use as many double vowels as possible (every sentence other than one word utterances should have atleast one double vowel), and refrain from using c (c sound is not really used in the language). "A"'s are heavily used. In addition to this they pluralize almost exclusively with "i" in the case of words ending with a consonant and "r" when the word ends in a vowel, as this is consistent with actual Quenya language rules. Sylvans have a great fascination for language and know many languages, because of this they often preface long sentences with "Aas-yi-kobor-wouuld-blaah, <insert sentence in standard kobo>".

Common word examples include (notice examples only some of these words may have a true sylvan word):

wood = wuud food = fuud could = kuuld would = wuuld

cider= siiduur fight= fiight lose = luus nature = naytuur to = tuu

Numbers (use these instead of english numerals):

zero = Zuuth one = Aash two = Duub three = Gaakh four = Fuuth five = Kraak

six = Bluug seven = Uudu eight = Tuukh nine = Kriith ten = Aash'Zuuth

Commonly used Sylvan Specific Language List (use these instead of kobo words):

Pronouns: I/Me/My = Ni Us/We/Our = Nia You = Yi you all = Yia He/She = Ti They = Tia everyone = tira Grouping words: fight/kill = upruut magic/power = vala health = saap dead = stump (ni-a-stump) rez = rosse root/mez = vine/vini (ni-koviired-dim-in-vini) xp = aging bubble (of xp) = seed level = ring (ni-gaiined-anuddir-ring!) move/go = ruma group = grove bind = laay-doown-ruuti horse = graazer General words: Greetings = Aiya Farewell = Naiya go away = Heka! Yes = Yaa No = Naa multi purpose interjection = Ai! @*&^ = skaah thank = Hanta (Hanta-yi) hoowah = huuah understand = gruuk the = i and = ar

Internet Related Terms: LD = Fell (as in Timmmbeeerr) Lag = Dropping Leeaves alt/secondary = wild oats Armor/weapons: armor(general) = baark (like leatheer-baark) weapons(general) = thoorns Hammer/blunt = Olba Sword = Eket Axe = Luusk spear = Tehta Bow = Luva HtH = Karka Extended common word list (stuff like seasons): winter = hrive fall = yavie spring = tuile summer = laire cold = nique dark = morna night = lome branch = olba cave = hrota forest = taure land, world = soil cheif(their version of nob) = ingwe commander (used similar to wargoth/klangoth) = kano