EDIT: Note to anyone who may be reading this years later: there's some inaccuracies (or, rather, extreme simplifications) in the discussion below, mostly regarding the derivational morphology of nouns and verbs and such. The other stuff, about conjunct verbs etc., is still correct
Tidbits from Ojibwe! Yay! Many of these features apply to Algonquian languages more generally, as well.
The Polysynthetic Conlang thread already has a great deal of information on how polysynthetic languages work; Ojibwe certainly isn't as polysynthetic as they come, but it's not too shabby either (my favorite example is the word aniibiishaabookewininiiwiwag, "they are Chinese." It's made up of seven morphemes, aniiby-ish-aaboo-ike-inini-iwi-wag, elm-PEJORATIVE-liquid-make-man-be-PLURAL. More literally, it could be translated "they are leaf-liquid [i.e., tea] makers." And "leaf" in "leaf-liquid" itself is more literally something like "pathetic elm tree").
Verbs are by far the most interesting words. They can be preceded by prefixes called "preverbs," which provide information about the manner, time, location, or properties associated with the action (e.g., bimaadizi, "he lives," combined with the preverb oshki-, "young," yields oshki-bimaadizi, "he is young," and the root -biisaa-, "to rain," combined with the preverb ishkwaa-, "after," yields ishkwaabiisaa, "it stops raining"). Verb roots can sometimes be simple (-odamino-, "to play;" -abi-, "to sit, to be at home"), but the great majority are either derived from nouns or other verbs by means of derivational suffixes or are compounds of multiple morphemes, usually a basic root with an "initial" which adds meaning. For example, there is a suffix -ikaa, which forms from nouns verbs with the meaning "there is a lot of [noun], there are many [nouns]." When combined with the noun manidoons, "bug" (itself derived from the noun manidoo, "spirit," and meaning literally "little spirit"), it forms the verb manidoonsikaa, "there are a lot of bugs." Combined with the noun nibi, "water," it forms the verb nibiikaa, "it's wet out" (i.e., "there is a lot of water"). Or, for some examples of verbs built from descriptive initials prefixed to more general verb roots, consider the root -amanji'o-, "to feel." Among the verbs derived from this verb root are inamanji'o, "he feels thus, he feels a certain way" (initial in-, "a certain way"), dakamanji'o, "he feels cold" (initial daki-, "cold"), minwamanji'o, "he feels good" (initial minw-, "good"), and ayekwamanji'o, "he feels tired" (initial ayekw-, "tired"). Or take the verb root -batoo-, "to run." Among the verbs derived from this root are biijibatoo, "he runs here," gizhiikaabatoo, "he runs fast," maajiibatoo, "he starts off running," and bimibatoo, "he runs along, he runs by" (the closest equivalent to English "run;" examples from Nichols and Nyholm, A Concise Dictionary of Minnesota Ojibwe, 1995).
Many verbs also specify, with suffixes, the animacy of their subject or object, depending on the verb class (Ojibwe nouns have an animate/inanimate gender system). For example, take the root -maanaad-, "ugly." The animate suffix -izi yields maanaadizi, "he is ugly," while the inanimate suffix -ad yields maanaadad, "it is ugly."
Another neat thing about verbs: a number of them contain morphemes which specify the quality of their subject nouns (e.g., if the noun is stringlike, or clothlike, or mineral, or liquid, etc.). For example, agaasaabikad, "it (something mineral) is small," agaasaabiigad, "it (something string-like) is small," agaasaakwad, "it (something stick- or wood-like) is small," and agaasiigad, "it (something sheet-like) is small." It is not optional to specify these qualities; if the object being described as small is a stick, the form agaasaakwad must be used, not some general verb meaning "be small" (although among younger speakers this is often no longer true). Body parts and instruments are often incorporated into the verb. For example, bookonike, "he has a broken arm" (c.f. -nik-, "arm"), bookogaade, "he has a broken leg" (c.f. -kaad-, "leg"), and bookojaane, "he has a broken nose" (c.f. -jaanzh-, "nose").
There are also three so-called "orders" of verbs: imperative, conjunct (used in subordinate clauses and in certain other complex situations), and independent (all other verbs). Conjunct verbs are very interesting. They are most often used to mark verbs as subordinate (e.g.,
gaawiin gii-bi-izhaasiin gaa-aakozid, "he didn't come
because he was sick, where the independent form of the second verb would be
gii-aakozi, "he is sick;" example from
here). However, I just finished reading a really interesting article on conjunct verbs: Rogers, Jean H. (1978).
Differential Focusing in Ojibwa Conjunct Verbs: On Circumstances, Participants, and Events.
International Journal of American Linguistics, 44: 167-179. The article deals with a distinction among conjunct verbs between "plain conjunct" and "changed conjunct" (forms in which the first vowel in the verb complex undergoes a predictable ablaut). Rogers argues that plain conjunct forms are used in basic, neutral sentences, while changed conjunct forms are used to place special focus on some aspect of the verb, either the circumstances surrounding the action, the participants involved in the action, or the event of the action itself. It's extremely fascinating, and I'm going to provide some examples from Rogers (though altered somewhat to fit the dialect I have so far been describing, Southwestern Ojibwe as spoken in Minnesota and Wisconsin):
An example of the neutral conjunct is in the sentence
Mii sa azhigwa de-apiitizid (it.is thus now
enough-be.of.a.certain.age-3SG.SIMP.CONJCT), "It's that
he's old enough now." A changed conjunct form, however (also involving the initial
apiiti-/
apiichi-, "extent"), focuses on the circumstances surrounding the action; in this case, the degree or extent involved; for example,
gaawiin ingii-gashkitoonziin ji-onishkaayaan gaa-apiichi-zegiziyaan (not 1-
PAST-be.able-
NEG to-get.up-1
SG.SIMP.CONJCT PAST.CHANGED.CONJCT-extent-be.scared-1SG.CONJCT), "I wasn't able to get up,
the extent to which I was scared" (i.e., "I couldn't get up I was so scared"). Or, to take a different example, using the preverb
onji- (changed conjunct
wenji-), "location," an example sentence using the independent order would be
Mille Lacs indoonjibaa (Mille Lacs
1-come.from), "
I'm from Mille Lacs." An example using the changed conjunct, however, is
Mii iwidi wenjibaayaan (it.is over.there
come.from.CHANGED.CONJCT-1SG.CONJCT), "It is there
that I come from; that's where
I come from," with the focus on the location, rather than a just being a neutral statement.
Verbs can also place focus on their participants through the changed conjunct form. Nominal verbs, called "participles," are quite common in Ojibwe, and are simple third person changed conjunct verbs used as nouns, with the meaning "someone/something who is [verb], does [verb]" (a number of common nouns are actually verbs in participle form, for example
bemisemagak, "airplane," literally "something that flies along," the changed conjunct form of
bimisemagad, "it flies along, it flies past"). These can be interpreted as changed conjunct verbs placing focus on the subject participant of the action.
A final area on which the changed conjunct can focus is on the occurrence of the action itself. For example, there is the simple conjunt form in the clause
giishpin oodetooyaan (if
go.to.town-1SG.SIMP.CONJCT), "if
I go to town." The changed conjunct form appears in the verb
wedetooyaanin (
go.to.town.CHANGED.CONJCT-1SG.CONJCT-ITER), "
whenever I go to town." Rogers points out that in this case "reference is to particular repeated events" (175). In other words, the focus is on the occurrence itself, and not just a neutral statement.
Okay, that's all the time I have for now. I should talk about the direct/inverse system, but I think the
Wikipedia article covers it fairly well. And there's also more info on Ojibwe grammar in
its Wikipedia article.