WNW: More on Passive Voice: Hi, Ambiguity!

A couple of weeks ago we discussed what passive voice is plus when it's actually okay to use it, even though writers are told over and over again to avoid it.
That post got some comments (hey, that phrase was passive :-D) about whether some sentence structures were passive, and I promised to clarify.
The example cited was:
She was excited.
IS that passive? It does have the key word was in there.
The answer: No, that sentence is most definitely NOT passive.
Except. English has some great ambiguity built into the underlying context. So all by itself and out of context, no, that sentence is not a passive construction. But it could be. (We'll get to that in a second.)
A similar example, showing why it's NOT passive:
Sarah was sad.
That sentence can't be passive; nothing (or no one) is being acted upon. We're just describing a state of being for the subject (Sarah), not what's happening to her.
You could make that kind of construction passive:
She was excited by putting up the Christmas tree.
Check it out: now it's passive. She's not just in a state of excitement; she's being acted upon (putting up the tree), which makes her excited.
Here comes the funky ambiguous part:This kind of sentence construction (he/she/it was ____) is ambiguous in English because the sentence could imply that something is being acted upon.
Basically, in some contexts, you could figure out what's making the person excited (versus the fact that she just IS excited).
If you have an entire conversation (or, in writing, a paragraph or whatever) where we know why she's excited, what's causing the excitement, then it's passive. In Sarah's case, we know her excitement is because of the Christmas tree.
So "She was excited," while not grammatically/structurally passive, becomes contextually passive.
Upshot there:
She was excited could be passive . . . or not. Technically it isn't from a grammar standpoint, but the final meaning depends on what the speaker intends.
Again, based purely on the structure, and if we're just explaining her emotional state, then no, it's not passive. Not even close.
Another ambiguous example:
The turkey was cooked.
We could simply be stating a fact about the turkey: We have poultry that is not longer raw.
Say a story explained how they knew when it was time to eat Thanksgiving dinner:
The turkey was cooked.
That's not passive. It describes the state turkey. (It's toasty hot, juicy, falling off the bone, and ready to eat. Yum. Pass the cranberry sauce.)
To make it passive, we need the person who did the cooking to be implied:
The turkey was cooked. [And we, the reader/listener, know Paula did the cooking. The turkey was cooked by Paula = passive.]
(Is this making any sense?)

Here's my linguist dad's key way of explaining passive voice:
Passive voice is when the grammatical subject is ALSO the logical object.
© 2010 Annette Lyon, all rights reserved