Washington (CNN) Ben Carson's former campaign manager said Wednesday that the neurosurgeon's lack of political experience -- coupled with his refusal to learn or use the "Washington lexicon" -- contributed to his campaign woes.

"He's also a 64-year-old African-American male, who culturally is what he is right? He's not comfortable with homosexuality, right?" said Barry Bennett, Carson's former campaign manager, at an event at Georgetown Institute of Politics and Public Service.

"And there was nothing we could do to make him talk about it in a lexicon that is much more modern," he said.

When asked about the comments from the former staffers, Carson's communications director Larry Ross said the campaign is "moving forward in a positive direction."

"(Crowds) are enthusiastically responding to (Carson's) values-driven message, forward-leaning policies and commonsense leadership," he said in an email to CNN.