Babies learn a LOT faster from parents than from DVDs - in fact, most studies show that children learn nothing from TV unless the parent joins in too.

DS was a very early talker and what helped him was just me talking to him. He would get told all about how plants grow or why we wash our hands or just naming the animals in a book. I'd read to him and tell stories. He now picks up a book and reads it to me - OK so he's just telling me what the picture is about but he's "reading" and making up things with it. He is using sentences usually and has great adjective use (for a toddler ie just sizes and colours and the odd emotional word like nice or cute), he has been able to ask for things for ages... but a word of warning.

They pick up words so well and so fast you want to watch your own language. Not just swearing - I ask DS what he would like now, as I hated him saying "I want..." all the time! Took about a month but we now have "I would like porridge for breakfast please." (OK it sounds more "Ah duh like porridge a breakfast pliz" but that's what he means!) He hasn't seen his dad for a month, but this morning came into our room, saw DH had gone and told me "Daddy has gone to work now. Bye bye Daddy." instead of asking "where Daddy gone now?" which I thought was great.

Honestly, if your son has a thirst for knowledge point out letters on street signs as you walk along. Count how many stairs there are. Run your finger under the words you read in books. When you use a verb, do the action (eg when you say jump then give a little jump). Singing and songs with actions are fantastic. Watch TV together: tell him about what he's seeing there. Maybe use some foreign words: DS has picked up some French, German, Italian and Spanish now. He may not be fluent but it will help him a lot when he needs these languages. You should hear him say "molto bene!" or "nada!" or "oooh, croissants, c'est bon!" or just a little "danke" instead of "thank you". I think it's cute but then I always aspired to being a polyglot as a child.