Each child demonstrates a unique “fingerprint” when it comes to the units in their language repertoire. Just as no two fingerprints are alike, no two language profiles are alike. Kids learn words, word parts, and word combinations that they’ve realized are important in their own lives, and so there are as many different language fingerprints, or language profiles, as there are word learning environments: approximately 300 million in the United States alone. The emphasis is that each one is unique. The implication is that the most effective language teaching paradigm would account for this individuality.