We were once asked to develop a certificate for LingQ. Here is what it looks like.We can do this for any or our members. It requires taking both oral and written tests with one or more of our tutors. One day we hope to add a cloze test to confirm the known words total. Remember we count only the passive knowledge of words. On the other hand the oral and written essays will demonstrate the active vocabulary of a learner. I think that tracking the activity of the learner during the period is in some ways more important, especially if this certificate is required by a third party who is paying.