Want to raise a bilingual child. Should me and my wife speak different languages to our newborn right from the beginning?

Five to six years of age is too late. The most critical period is between 6-8 months. This is the critical period for sound development. At 6 -8 months, babies are listening intently to us, and they're taking statistics on the language that they hear as they listen to us talk. Watching TV and hearing audio does not help much. The most critical thing to do is to have a human being conduct lessons for about 12 intensive sessions. Watch this Ted Talk to learn more: https://www.ted.com/talks/patricia_kuhl_the_linguistic_genius_of_babies