Sleeter and the zone of proximal learning

I was very interested in the Christine E. Sleeter reading and her conversation her emphasis on framing a students learning around their lives, connecting the classroom to their home and using this knowledge to reinforce their learning. She goes though several examples of how teachers can do this, and provides a structure for understanding the backgrounds of the students. I think this can be a powerful tool with students for a variety of reasons, mostly because this makes a student comfortable in their own classroom, using terminology and situations that they are comfortable with as a framework for learning hard classroom materials. Having access to even the language of the classroom is a huge step and learning and as someone who spend most of her time in classrooms where precise and incapable language is normal; I know that by not understanding one word-not a concept — but a word, can hinder learning until that student has caught up. While I was reading this article, I kept thinking... what about the tests? I believe that this method of learning is very effective, but I kept thinking about what happens when these students are put into a situation that isn't catered to their background and outside lives. But then I thought, but by that point that are comfortable with the topics, they understand them as they have taught them so personally. 

Another aspect that I admired from her writings is the respect and devotion required from the teacher. She called for teachers to know the lives of their students and and community and to incorporate that into the classroom. She wanted teachers to talk to members of the community, asking questions that were desired based ( and a few deficit based their at the end). But figuring out the dynamics of the community. A hesitation I have on this, is asking a teacher who is new to the community attempting to teach to the community. I fear they might make jump and stereotypical judgements on the type of community and members of the community and from that point on might unintentionally reinforce inequalities in their own classroom.