As you know, however, most schools in the United States are required by law to test all students who speak a language other than English in their home. These language proficiency tests are required to be standardized and normed. But I think we should be honest about what is being assessed. Language proficiency tests provide us with a snapshot of one student's language use. This may be a very meaningful snapshot, but it should not be the only evidence of a student's language ability.
People learn by doing things together, and knowledge itself is something collective.
Knowledge of a language, for example, is highly dependent on the interaction in which that language is being used. Language proficiency, then, is the language that can be created collaboratively in a particular situation for a specific purpose. Portfolios may include a number of observations made over time and in a variety of situations by instructors and students alike. This might not seem as practical as a traditional standardized test, but in the long run, it probably will be much more practical since the assessments it gives will be more valid. Any test is measuring the kinds of learning that happen interactionally.