Ash's Pikachu/Personality and characteristics/Pikachu's language

Some of Pikachu's speech is consistent enough that it seems that some phrases actually mean something. (In Stealing The Conversation!, refers to this language as "PikaSpeak," but this most likely isn't official.) For instance, Pikachu always uses "Pikapi" when referring to Ash (notice that it sounds somewhat similar to "Satoshi"). Other speech includes:
 * Pi-Kachu: Pochama (Piplup)
 * Pikachu-Pi:  (Misty)
 * Pika-Chu:  (Brock), Kibago (Axew)
 * Pikaka:  (Dawn)
 * PiPiPi:  (Togepi)
 * PikakaPika: Fushigidane (Bulbasaur)
 * PikaPika: Zenigame (Squirtle), Mukuhawk (Staraptor), Goukazaru (Infernape)  Gamagaru (Palpitoad) or Marilli (Azumarill)
 * PiPi-kachu: Rocket-dan (Team Rocket)
 * Pi-Pikachu: Get da ze! (He says this after Ash wins a Badge, catches a new Pokémon or anything similar.)
 * Pikachu may not be the only one to use this phrase, as other Pokémon do this as well. For example, when Iris caught Emolga, Axew said Ax-Axew (Ki-Kibago in the Japanese). This also happened when Iris caught in SS028.
 * Pika-Pikachu: When referring to or introducing himself.
 * Chaa: Anything he says happily or excitedly, or when yawning.
 * Pika!: "Matte!", or saying "Wait!"
 * Pi-kaPika: "Sayōnara," or saying "Good-bye."