Yoda DOES indeed speak with ridiculous inverted grammar in ESB--when he is prentending to be a crazy local!
"Away put your weapon, I mean you no harm"
"Help you i can, yes"
"Take you to him, I will"
"ah, father, powerful jedi was he"
Then Yoda reveals that he is in fact a wise and powerful jedi master.
"I cannot teach him. The boy has no patience."
"Much anger in him, like his father"
"A jedi must have the most depest committment. The most serious mind. This one, a long time have i watched, all his life as looked away, to the future, to the horizon, never his mind on where he was, what he was doing."
"That place is strong with the darkside, and you must go."
His speech is pretty normal, with only the odd, MINOR inversions, such as "told you i did, reckless is he", which is about as extreme as it gets. Yoda's repuration of course is that he is this weird gibberish-speaking inverted kermit, mostly because of the introductory "crazy Yoda" scenes--in fact, even Lucas forgot this. Yodas PT grammar is the same as his "crazy Yoda" grammar!
Can you imagine if GL wrote ESB now? "Teach him, I cannot. No patience the boy has" "Stong with darkside that place is, and go you must"