given a reading level and a range. Books rated below their level are easy to read, while books above their level challenge the student. Sometimes students are not even allowed to check out books from the school library that are outside their range. Vygotsky argued that a major shortcoming of standardized tests is that they only measure what students are capable of on their own, not in a group setting where their minds are being pushed by other students. In the context of second language learning, the ZPD can be useful to many adult users. Prompted by this fact as well as the finding that adult peers don't necessarily need to be more capable to provide assistance in the ZPD, Vygotsky's definition has been adapted to better suit the adult L2 developmental context. Scaffolding The concept of the ZPD is widely used to study children's mental development as it relates to educational context. The ZPD concept is seen as a scaffolding, a structure of "support points" for performing an action. This refers to the help or guidance received from an adult or more competent peer to permit the child to work within the ZPD. Although Vygotsky himself never mentioned the term, scaffolding was first developed by Jerome Bruner, David Wood, and Gail Ross, while applying Vygotsky's concept of ZPD to various educational contexts. According to Wass and Golding, giving students the hardest tasks they can do with scaffolding leads to the greatest learning gains. Scaffolding is a process through which a teacher or a more competent peer helps a student in their ZPD as necessary and tapers off this aid as it becomes unnecessary—much as workers remove a scaffold from a building after they complete construction. "Scaffolding [is] the way the adult guides the child's learning via focused questions and positive interactions." This concept has been further developed by Mercedes Chaves Jaime, Ann Brown, among others. Several instructional programs were developed based on this interpretation of the ZPD, including reciprocal teaching and dynamic assessment. For scaffolding to be effective, one must start at the child's level of knowledge and build from there. One example of children using ZPD is when they are learning to speak. As their speech develops, it influences the way the child thinks, which in turn influences the child's manner of speaking. This process opens more doors for the child to expand their vocabulary. As they learn