he was the first rapper i ever saw, "pop the collars". when someone lifts the collar on their shirt two times
has introduced words such as "scrilla", "cheddar", "cheese", "broccli", "lettuce" "san yay" "yay area" and a host of other terms that are used by many rappers. hes also been doing the "fo sheezy" rhyming stuff for years, which snoop dog picked up on and started using "fo shizzle" which is trendy nowadays.
he makes up a new word every album. part of the reason he isnt well know because he still is for the most part a california rapper, and his albums mostly circulate in northern california.
On the other hand, he was almost definitely one of the very first to start using the "-eezy" verbiage, which derived from "-izzo" as in "a hizzo, a hizzo should I save her?". He also has spawned other similar dialect modifications such as what's crackulatin or crackalackin. E-40 is also responsible for bringing the word flashin to the masses. Before he started using it, I recall it only being used by friends from Oakland and never on a track.
One of the very first E-40isms to become part of the bay area dialect was Captain, referring to a sucker that breaks himself for a hoodrat.
Which brings me to my next point. While E-40 was probably best known for Captain Save-A-Ho amongst his bay area fans, and sure Hurricane was one of the best known tracks of The Click, but technically it was not his song, and regardless neither was as popular as "One Love", "Rappers Ball", "From the Ground Up", or "I Hope I Don't Go Back", all of which got significantly more air time outside of the bay area.
E-40 reps Vallejo first, 707 second, The Bay Area third, and Northern Cali fourth. I've never heard him show a preference for the east bay (510) over any other part of the bay.
Finally, E-40 is a rapper. He is not a so called hip-hop artist or what have you. Very little hip-hop came from the bay. Certainly some of the most creative and imaginatively lyriced (yes I used lyric as a past tense verb, so what?) rap came from the bay, but the only significant hip-hop has been The Pharcyde, Blackilicious, and Mr. Lif. E-40 goes to a studio where original tracks are produced on Korgs, beat machines, and pro tools, and no DJ!! and therefore is NOT HIP HOP! Even back when a DJ played a more prominent role in his music, the original beats with roots in freestyle music (aka latin hip-hop, where samplers and beat machines and the producers who run them are the foundations of the beat) define 40's music and place it firmly in the rap category.
One more thing, cats in the bay was hyphy before E-40 gave it to the world, but someone would have to be pretty hard headed to deny that his name has damn near become synonymous with it.