From someone who is both an unschooler and an early intervention worker. Disclaimer: this is of course based on the very little info I have from your posts and not actually observing the child, but from my 12 years of experiance, heres what I see: Just from what you posted I counted 25 words (not just the list, but including the "whats this" etc you said she does). IME, you will never never never get a full list on the spot like that, becuase you cant possible remember every word youve ever heard her say. Plus, two word phrases dont happen until basically 50 words are there. SO I feel safe in saying she probally has about 50. If you want a good, accurate count, do this: keep a list, write down the ones you told us, then put the list on the mantle, on the fridge,somewhere visible and accessible and for the next week or two, add to it as you hear words that you dont have on the list. You will probally be surprised at how many she has. If its meaningful, it counts. In other words, if "gaga" ALWAYS means grandma, then yes, its a word.
It takes, as a general rule of thumb, about six months to lose your native lang. I have had people say, "she didnt HAVE language". Yes, she did, even if she was preverbal she was hearing a diffrent language. So, you basically were starting from scratch at 12mos for lang development. Shes two and a half, if she were still a year behind, she'd be at about an 18mos old level, but even begining to combine two word phrases puts her more about 24 mos, so... even though a bit behind, she has caught up, as in, the gap is closing,if you see what I mean.
I also noticed you said she walked at 14mos. While that isnt exactly far behind, its a bit later than the "norm" or average of 12mos. This is only impotant because, by and large, most children (not all, but most) do not talk until after they walk. Therefore, if there is a two month delay on walking, I expect the same for talking. Another general rule of thumb.
So, Id say, if she is understanding you and she is progressing (she hasnt either stalled out nor started to LOSE words), you are probally ok. Oh, also, normal attention span is approximately three to five min per year of age. So at two years old, six to ten min. is all I'd expect.
All that said, if she spent those first six months in an orphanage, there is always risks of delays due to lack of stimulation. But IMO and IME, the biggest risk is always emotional becuase of lack of bonding, so if you have knocked that out, you have already done the best thing you can ever do for her!! (And Im sure you have!).
THere are things you can do at home. But if you want professional intervention that is also appropriate intervention for her age, contact your local early intervention program. These programs vary from state to state but every state has one (for zero to three) by federal mandate and they should be free or use a sliding scale. Im in Texas, but just for example, I think a family of four has to make like 40,000 before they would even have a minimum payment and the min. is ocnly $20 per month no matter how often they come out. They should also come to your home, at least we do here, and rather than "doing" therapy TO your child, we give strategies to YOU , things you can just add in to your daily routine to help stimulate language development.
Also, just my personal experiance, all of my kids were slightly behind at two, but by three, holy cow!! And since she is the youngest, well, sometimes there isnt as much of a NEED....ie, someone else always asks for cookies, snack, story etc, so she doesnt need to request much.
But you know you're child better than anyone else. What is your gut feeling? Is she normal in every other way? If you arent concerned about her receptive lang or cognition or social skills etc, then Id say just read to her, label actions, objects and emotions for her etc. Add to her words, ex: when she says "bannana", YOU say, "yellow bannana" or "eat bannana" etc
All the recent studies suggest that the type of therapy where you take the child out of their natural environment and make them sit and do drills is nowhere near as effective as embedded intervention (basically, play with them and add the learning in, they wont know its "therapy", its play which is how children learn, we all know that!!!)
Ok, sorry, feel like I wrote a book!!! Hope it helps!
eta: here, if the ONLY issue is expressive language ONLY, a child has to be a full SIX MONTHS delayed to even qualify for services! So if your dd is six mos behind, it would be a toss up here if we would even consider that NEEDING intervention. Just to put it in perspective for you. All other delays it only takes two months of a dealy to qualify. They changed it becuase of the overwhelming number of kids that were enrolled for expressive lang only. which makes me think: how many kids have to be "delayed" before we call it "normal"?
edited agian becuae I jsut realized youre in canada, so forget what I said about contacting your early intervention program, DUH!!!!! But I think there are plenty of things you can do at home and most of it is stuff you are probally already doing.