From the start, we did not allow background TV in our home. We didn't allow any active TV either. Until our daughter was 1 year old, we did not turn on the TV. Why? Because we read studies that language development is dependent upon a few factors - and that background voices confuse the developing brain. My guess is that this helped us tremendously. Our daughter's first words were at 5 months old. She said, "corn bread."
From the beginning, we bought a lot of books. The best ones, we have found, are the Bright and Early Beginner books by Dr. Seuss. I'm linking an Amazon wishlist - no, you don't need to buy us any books - I made this list for everyone else to see the books that worked best for us. We read to her night and day. When she was big enough to reach the books on her own, she'd bring us entire piles of books to read. The library of books listed do a lot to help your child with phonemes. They're learning words that you don't speak to them every day, but are important to building their vocabulary. The rhyme scheme helps as well.
Update: January 24, 2017 - Our daughter is now 19 months old. She knows and says her entire alphabet, can sing about 40 songs, can count to 12, says and knows her shapes and her colors. She is VERY verbal, speaking in full sentences. She uses a multitude of words. At 12 months old, her vocabulary was up to 800 words. It's far surpassed that now.
She has her own iPad now and I highly recommend the Smart Baby Big Box of apps. It's wonderful. There's an app-bundle that I would recommend starting at about 18 months. She's so fast at this stuff. It's wonderful and it's taught her all of her shapes and confirmed her learning of colors.