He clam about the structure of interlanguages can be derived
from gramnatical theory, and like natural language, interlanguages can be idealized to make them amenable to linguistic analysis. He added that the universal generalizations that hold for the primary languages also hold for
interlanguages. Eckman(1991) claimed that interlanguages are languages and, further, that proposed linguistic
universals are fully universal, in the sense that they apply to non-primary as well as primary languages.