As World Language teachers, I believe we are already doing this in some way through ACTFL's proficiency guidelines. These guidelines are not just a teacher tool, but a way to communicate with parents, students, and administration about where students are currently and where they can go. By using the proficiency guidelines with students, we instill this growth mindset - this is what we know you can accomplish with hard work and practice.
The guidelines are used in a myriad of ways to help students self-assess and manage their own growth. If they know their strengths and weaknesses, we, as teachers, can help them focus their efforts toward improvement. Laura Sexton shared a rubric in her Central States 2016 presentation that she uses with students to continually push them to grow and improve. By providing students a base from which they can grow, she encourages the growth mindset in her students. Tweak little things and you can progress in your language learning.
We we also build on the growth mindset with our students as we build a unit. At the start of each unit, the teacher provides input and asks students to produce less than they take in. As the lesson builds, so too do the language requirements. Further, each of our activities build students' communication skills until they are ready and capable of communicating around the learning targets. The Integrated Performance Assessment (IPA) then asks students to demonstrate their growth with a situation with which they have come to be familiar. Teacher and students build the language together, building students' confidence to demonstrate their growth.
The final piece is how the teacher interacts with her students. Instead of praising their intelligence or smarts, we need to focus on their hard work and continued effort to improve. Dweck talks about the "transformative power of effort" as a way to "change your ability". This is the message we need to drive home to our students. It isn't about error correction or perfect grammar, but comprehensibility. Each time a student feels they are understood, they are one step closer to knowing their effort is worthwhile. As we push our students to greater performance, and eventually proficiency, it is important to celebrate their risk-taking, their effort, and their ability to communicate, no matter how insignificant or small it may seem at the time. That means leaving behind the idea of perfection, whether grammar, pronunciation, syntax, etc., to favor the comprehension of target language input, the ability to communicate, even at the word level, and the interest and excitement around language learning as a whole.