No. The only games where Pokemon can "speak" is Pokemon Mystery Dungeon.
You can't talk to your Pokemon in Pokemon Platinum. Only in Pokemon Heartgold and Soulsilver.
Arceus
You face them and press A.
talk to rowan
complete the sinnoh pokedex and talk to professor rowan.
velistone city behind the Pokemon ceter talk to the ppl inside.
go to Sandgem town and talk to the girl that says which Pokemon is where
Talk to Bebe in the house next to the Pokemon center in Hearthome city.
No, it can't.
Talk to the guy in floroma meadows
Talk to the mansion owner after you get the national pokedex
route 209 talk to the fisherman