The San Diego Chargers take on the Oakland Raiders on January 1, 2012 in Oakland, California.

The National Football League (NFL) has launched voice-recognition content for Amazon's virtual assistant Alexa that will teach fans about players, rules and the history of American football.

Rolled out on Thursday, "The Rookie's Guide to the NFL" will allow users to ask Alexa-enabled devices questions about the sport. The Alexa skill – a downloadable add-on – is available for free in all of Alexa's English language regions. It can tell users about the technicalities of the game and define more than 1,000 NFL terms, rules and jargon such as "encroachment" and "snap count."

Users who enable the guide on their device can ask for a random fact or specify questions such as "How tall is Aaron Rodgers?" or "Who won Super Bowl 35?"

The guide also has content to help fans prepare for the Super Bowl, weekly playoff previews from Super Bowl winner Osi Umenyiora, and bios of every active NFL player.

The NFL defined the content as "a guide for everyone, from newbies to experts," on its website.

Using Amazon's Alexa platform isn't the sports giant's first venture into voice recognition technology. The NFL already offers an add-on for Google Home devices, "The NFL in :60," which provides daily news updates.