DVD's have not been very useful for teaching my kids language. At most they've picked up a few words. In my opinion, they need to be spoken to to pick up language--especially at your son's age.
I'm in a different boat than you in that I grew up in a bilingual household and can converse with someone somewhat easily in Spanish. BUT I am far from fluent, make a TON of mistakes, and was very insecure about speaking to my kids because I thought I'd be teaching them all wrong.
Do you have the pronunciation down in Spanish (or French)? If so I can tell you what I've done that has worked really well so far. I started by teaching my kids a lot of vocabulary. This can be done while speaking in English, and just using the Spanish word for something. ("Would you like leche or agua to drink?") Also my son happens to love flash cards, so we use those. And I almost forgot, Usborne 100 and then 1000 Words in Spanish has been extremely helpful!!! All of this was very helpful in building up their vocab, but it would obviously never teach them the syntax or anything else. So I made a list of the PHRASES that I most commonly use in different parts of the house and put a list on the wall, where I could see it easily to remind myself a) to speak in Spanish, and b) the correct grammar of what I wanted to say.
Think about it...how many times a day do you say "Put on your boots" or "Have you made a pee pee?" Maybe I'm just a little too repetitive:tongue_smilie:, but I find that I am mostly saying the same things over and over (especially to children your son's age.) I mean you aren't discussing rocket science...its mostly "What would you like to eat?" and "time for bed." Isn't it? So now, I just say all of those phrases in Spanish, instead of English. It works wonderfully. The kids pick it up quickly, and I don't feel insecure because I know I'm using the correct grammar and not just making something up on the fly which might or might not be wrong.
Also, I find that this really approximates how a child would learn if the parent was fluent...they are learning by being spoken to, in a very natural way. I am not demanding that they speak back to me, and just am letting it develop in its own natural way. For instance, if I ask my son "Donde esta tu hermana?" he'll give me an appropriate answer me in English. But if I ask him "What does hermana mean", he probably couldn't tell me. That's fine with me--he's understanding the word in context, and some part of his brain obviously knows the word, even if he isn't able consciously translate it yet, which I think is a different skill. Another example: My daughter will say "Tienes hambre" instead of "Tengo hambre" because that's what she's used to hearing. I figure that's just the equivalent of a baby saying "Me hungry"....which we wouldn't correct. I figure it will iron itself out eventually. Also I never make them have forced conversations like "what is your name?" "My name is..." I did try, but it was like pulling teeth. I find that they are talking more and more on their own. I try to make it seem like something cool--some extra skill that they have--instead of something with a lot of pressure attached to it.
I guess my point with all of this is that I looked at more formal ways of teaching Spanish--DVDs, workbooks, etc., but from my experience none of them could ever hope to teach more than the colors, numbers, etc. Since I've been using the phrases in daily life, I've seen that my kids Spanish has really exploded. Every week I try to include more phrases. Its a constant struggle for me to try to remember to use them, but it has really paid off. And I really feel like they are learning 'real' Spanish instead of just numbers and colors.
To get the phrases, first I spent a few days listening to myself and jotting down the most common phrases. (Take off/put on your shoes/jacket...; what do you want to eat; stand up; sit down; its time for bed; put your clothes in the hamper; etc. etc.) Then I went about finding translations for them, either online or in books (or asking my parents.) I have since found an awesome book that has just about everything you'd ever say to your kids in it. It is even geared towards homeschoolers and has a section on 'school at home' where the first phrase is "The bus just went by." :) Its called Kid Stuff Spanish. http://www.amazon.com/Kids-Stuff-Spanish-Therese-Slevin/dp/0960614028/ref=sr_1_1?ie=UTF8&qid=1287831512&sr=8-1 There are so many phrases in it, and they are almost all really useful. It has really helped me to think of even more ways to speak Spanish with them. (Such as when playing a board game "Its your turn." "Roll the dice.") The book is available in French, too, by the way.
I find it ridiculously expensive for a little book ($20), but I own a LOT of kids Spanish books, and this (along with the Usborne 1000 Words) has been by far the most useful, so its worth it. There is another book that is cheaper and has the same idea: Ana Lomba's Play and Learn Spanish. But there are many fewer phrases in that book, and I can never seem to find exactly what I want to say or something that sounds natural to me.
So my advice would be to just start doing it and I think you'll be surprised at how easy it is to work a few phrases in throughout the day. I can't even remember the last time I said "put on your shoes" or "hold my hand" in English. I mean its definitely not the same as having a parent that is fluent and able to teach more subtleties, but in my opinion its a lot better than nothing...and its also the best I can offer. When they're older I plan on teaching grammar more formally, and I'm hoping that all this will lead to fluency. For right now, this is really helping their oral skills develop.
