The 22-year-old Spaniard signed for the Blues in 2011, but has been limited to just 22 appearances in that time, and spent last season on loan at Valencia.
Romeu penned a new deal with Chelsea that keeps him at Stamford Bridge until the summer of 2017, however the former Barcelona youngster admitted that should the opportunity arise, a longer spell in Germany would be appealing.
"Maybe I am staying for a longer period of time," Romeu told kicker-Sportmagazin.
"You cannot rule anything out in football.
"I have experienced a technically demanding game in the Spanish league, football in England is more physical, and the Bundesliga is a mixture of that.
"My ambition is to quickly learn the German language."
Despite this, Romeu insisted his focus is to retain a first-team starting berth this season, and make the most of his opportunity.
"I want to help VfB Stuttgart achieve a good season and be a full part of the team," Romeu added.