What one first observes with regard to core slang morphology are the violations of the normal rules of word formation in standard speech. These violations may be related to use of affixes that are rare or absent in standard English; of affixes which are novel or functionally fossilized in standard English; and morphological structures that are rather difficult to determine.
Among the novel affixes let's mention the prefixes pe-. ke-, ge-, -he-, je- as in zazzle "sex appeal" - pizzazz "zest" thob "to be credulous" - kathob "vague object" - kazoo "resonator" zook "prostitute" - gazook "tramp" wallop "to hit hard" - chewallop "bang" moke "dull fellow" - jamoke "noisy party" tootsie - patootsie "beauty"
The use of novel affixes, however, may be less productive than that of old affixes that have become fossilized in standard speech. Slang here has a de-fossilization effect. Examples:
suffix -um as in jizzum = jizz "semen" in wampum "money"
A novel suffix that is diagnostic of slang is -o, which has a generally intensive force with strongly derogatory undertones. It is common is expletives like whammo! "bang" vocatives, like Danno "Daniel" stage names, like Groucho, for Julius Marx adjectives, like stinko "drunken, macho stump-words like ammo "ammunition" More recently -o has become a virtual morphemic fad in pseudo-Hispanicisms like floppo "failure dyno primo Other suffixes -erty flibberty-gibbet "scatter-brain" -ledy tiddledy-winks (a cup and disk game) higgledy-piggeledy
Infixes ebe and epe as in hullabaloo lollapalooza
eme, me, em, e as in thing-uma-jig "object" "whatever2 rig-ma-role "complication" thing-um-bob "object" flumm-a-diddle "nonsense"
Roger Wescott mentions a striking example of defossizliation : Liquid and nasal infixes appear both right before the nucleus and right after the nucleus of a word; their function seems to be vaguely intensive. Examples: bleep = beep "high pitched sound" scrooch = scooch "to sidle (on a sofa)" chunk = chuck "to toss" purp = pup "young dog"
These prefixes, suffixes and infixes are not listed as productive in present-day English word formation; but they are surely productive in slang!
Along the lines sketched here it might be possible to list a few principles for slang morphology and slang phonology. Nevertheless, some slang words still remain puzzling: Let's consider the word lollapalooza. The word exhibits palindromy, in loll diagnostic sounds, in -ooz- diagnostic affix pa- But what gives the word its most conspicuous lexical abnormality is the fact that its immediate grammatical constituents are unclear: loll-apa-looza lolla-palooza loll-a-pa-loo-za loll-a-pa-looz-a
One last point: Not only is slang characterized by a high degree of synonymality, but - at least if core slang items are considered - also by hyperpolymorphy, i.e. the occurrence of a plurality of alternants for most forms. This profusion of forms is equally evident among bound and free morphemes. As examples I might again adduce the examples of reduplicatives: ablaut reduplicatives, and rhyme reduplicatives.
Cockney English Adam And Eve Believe Almond Rocks Socks Apple and Pears Stairs Artful Dodger Lodger Ball of Chalk Walk Band of Hope Soap Bird & Lime Time Boat Race Face Brixton Riot Diet Brown Bread Dead Bubble and Squeak Greek Cock & Hen Ten Cream Crackered Knackered Currant Bun Sun Daisy Roots Boots Dancing Fleas Keys Dig the Grave Shave Dog and Bone Phone Drum and Fife Knife Duchess of Fife Wife Elephant's Trunk Drunk Fork and Knife Wife Forsyte Saga Lager Ginger Beer Queer God Forbid Kid Twist and Twirl Girl Weeping Willow Pillow Gold Watch Scotch Kane and Able Table Lemon and Lime Crime Ocean Pearl Girl One Time Looker Hooker Ones & Twos Shoes Oxford Scholar Dollar Paraffin Lamp Tramp Pat and Mick Sick Porky Pies Lies Rhythm and Blues Shoes Schindler's List Pissed Skin And Blister Sister Strange'n'Weird Beard Trouble and Strife Wife Tumble down the sink Drink Whistle and Flute Suit Simon J. Foote (firstname.lastname@example.org), 1997
An example involving bases only is
biff = boff = bop "to hit".
An example involving suffixes only is
geezle = geezer = geezo "old man".
And an example involving both bases and affixes is
dibbus = diddie = dingle "thing"
A phonologicalLy special case of hyperpolymorphy is provided by rhyme-tags or echo compounds which usually have denotatively meaningless components that arrange themselves in consonantal apophonic series. Examples were adduced under the heading of rhyme reduplicatives already
cheezy-peezy "Jesus" ugly - bugly "repulsive" holy - moly "Moses" palsy - walsy "excessively friendly"
Some cases of polymorphy involve the pyramiding of syllables. An example is the series of related slang-expressions for a stage-play that has scored a dramatic box-office success: smash -smasher - smasheroo - smasheroony - smasheroonio