DOUALA (Reuters) - A prize-winning New York-based Cameroonian novelist will be freed from jail and expelled from his native country after being held for nearly three weeks on charges of insulting and threatening the president, his lawyer said on Wednesday. Patrice Nganang was arrested on Dec. 7 as he prepared to board a flight to Kenya, and accused of insulting President Paul Biya. The government later said he had threatened Biya in posts on Facebook. A literature professor at the State University of New York at Stony Brook, Nganang was born in Cameroon and holds dual Cameroonian and U.S. nationality.  Nganang s lawyer, Emmanuel Simh, told Reuters that a judge had dismissed the government s charges and ordered his client released. Simh later said the authorities had retained Nganang s Cameroonian passport and that he would be placed on an afternoon flight to the United States.   According to (the government), he is an American who does not have a right to this passport,  Simh said. Nganang s supporters say the accusations against him were politically motivated and related to a Dec. 5 piece he wrote for Paris-based magazine Jeune Afrique, in which he criticized a government crackdown on Cameroon s English-speaking minority.  Since last year, the government, which is dominated by members of the French-speaking majority, has repressed protests by English speakers who say they are socially and economically marginalized. Dozens of civilians have been killed in unrest that has fueled support for separatists seeking an independent state. Some separatists have launched armed attacks on state forces, creating the most serious challenge to Biya s 35-year rule. Thousands of English speakers have fled across the border into neighboring Nigeria. Cameroonian law forbids adults from holding dual nationality, although the prohibition is unevenly enforced. Cameroon s government spokesman could not be immediately reached for comment. English speakers make up around a fifth of the population of Cameroon, which was formed when parts of a formerly British-ruled territory joined the larger, newly independent French-speaking Republic of Cameroon in 1961. The past year s violence is the latest example of how Biya s rule has grown increasingly intolerant of dissent, with opposition activists, journalists and intellectuals routinely arrested and sometimes prosecuted. A Cameroonian reporter for Radio France Internationale was released from prison last week after more than two years behind bars for contact with the Islamist militant group Boko Haram, in a case that drew international condemnation. 