By definition, a bilingual classroom is one in which all children are engaged in instructional activities in two languages. Indeed it does. A relatively recent innovation in American education has been two-way bilingual programs in which children are taught in two languages. In these programs, native English-speaking children are in class together with children whose home language may be Spanish or Chinese or Japanese. Instruction is in both languages.
Children have to learn to communicate in both languages.
And they do. By the fifth or sixth grade, it is difficult to distinguish native and non-native speakers. The children are truly bilingual. But current educational practice is hardly aimed at bilingualism. Many children who go through 'transitional' bilingual education programs, in which the native language is used as a bridge for learning English, eventually do learn English but at the cost of losing proficiency in their home language.