Clitics: Crazy Little Critters

Clitics have proven to be one of the hardest things to classify syntactically or morphologically (or in anything linguistics-related for that matter).  Supposedly, they have a long history of being studied since Pāṇini's time (Ancient Sanskrit linguist dating all the way back to 4th century B.C.).  Jakob Wackernagel (late 19th/early 20th century Swiss linguist who studied Sanskrit as well as Indo-European, Greek, and Germanic) also studied them making a generalized assumption on Indo-European languages roughly stating that they came after the first word in a sentence.  They are considered to be a phonologically deficient 'thing' occupying an unstressed position which is more of a reason to not place them first in a sentence.

Ok so I started all this talk and haven't mentioned what the heck a clitic is--well that's the thing I don't think I know but it's such an annoying little particle in MANY LANGUAGES that it still needs to be properly defined.  Oh and get this, there are different types of clitics as well.  Arnold Zwicky (1977) gives the definitions that I am most attuned to:  simple clitic which is "a free morpheme, [that] when unaccented, may be phonologically reduced, the resultant form being phonologically subordinate to a neighboring word"; special clitic which is "an unaccented bound form [that] acts as a variant of a stressed free form with the same cognitive meaning and with similar phonological makeup"; and finally bound words which defined by Fontana (1993) are "those clitic-like elements which do not have corresponding full forms" (whatever does this mean!!).

I most identify dative clitics, in Modern Spanish, with the second definition--being of the special kind.  The following is a paradigm that helps identify what Zwicky means:
   
     In Spanish we have:

1. "Yo" (I, subject pronoun), "me" (dative clitic), and "a mi" (me, object pronoun)
2. "Tu" (you, subject pronoun), "te" (dative clitic), and "a ti" (accusative object pronoun)
3. "El/ella" (He/she), "le" (dative clitic), and "a el/ella" (him/her)
4. "Nosotros" (We), "nos" (dative clitic), and "a nosotros" (us)
5. "Ustedes" (you all), "les" (dative clitic), and "a ustedes" (you all), "Vosotros" (you all), "os" (dative clitic), and "a vosotros" (you all)
6. "Ellos/ellas" (They), "les" (dative clitic), and "a ellos/ellas" (them)

Oh, and then we have the pesky reflexive se (which also has indefinite and passive uses) and a somewhat accusative object which is si (mismo).  There are also prepositional things which I really don't know how to classify: conmigo (with-me), contigo (with-you), and consigo (with-self).

Anyway going back to the beginning of this post--clitics are CRAZY!!! Anyone want to tell me what they hate most about them...?

References:
Fontana, J. M. 1993. Phrase Structure and the Syntax of Clitics in the History of Spanish. Ph.D. dissertation. Philadelphia: University of Pennsylvania.
Zwicky, Arnold. 1977. On Clitics. Bloomington: Indiana University Linguistics Club.

Wikipedia on Pāṇini
Wikipedia on Wackernagel
Wikipedia on Clitics