A portfolio in the foreign language classroom is a collection of a learner’s work that displays the progress that learner is making in connection with classroom goals. This assessment method is very learner-centered. A portfolio can contain student work samples, optimally chosen by both the teacher and the learner, that are based on the learning goals. Apart from being learner-centered and allowing ownership of learning, portfolios offer opportunities for self-assessment and therefore critical thinking processes (Which work is my best and why?) and for collaboration processes with peers, for example, when learners work together on one task for the portfolio.
TSAGARI, D., et al. Handbook of Assessment for Language Teachers. 2018 (adapted).

According to the excerpt, reflective assessment tools such as portfolios