Eric just started saying two-word sentences such as “dada home” and “doggie go.” about how old is eric likely to be?

Eric would likely be in between 18-21 months old. It is because between this age, it could make the toddler to speak in a way that they won't likely say it in whole sentences but bits by bits, or words per words. They may be able to speak words that they could hear or understand though they could only speak minimum words.