Yes, but if you can load a few lessons (assuming you're using the mobile version), but only a few...
Duolingo was created in 2011.
Duolingo and Memrise. I recommend duolingo.
yes,
Duolingo is 100% free. They want free language education for everybody.
Many products on the market today require wifi to work. Many of the smartphones today require an internet connection of some sort, usually wifi, to be able to download apps or do anything really on the phone.
you can download the Duolingo mobile apps and can learn there free of cost.
From what i hear, draw something does not require wifi.
no
Data is wifi. The only way a smartphone can use wifi without having a data plan is when it is connected to wifi at a building.
No, unless the place you are at require a charge to use their Wifi, but normally it is a free service
Yes, it will require an internet connection. Just like Skype ;)
You may be at a location that doesn't have wifi connectability. Or, you might be at a wifi location, but you might not have wifi settings (Settings > Wireless & Networks) turned on. Furthermore, even if you do have it turned on, that location might require a password to use it.