Background:
Previous research has demonstrated that preservice teachers can professionally notice in an authentic field placement context while engaging in lesson study with a facilitator and a classroom teacher.

Materials and methods:
This qualitative case study examined the specific lexical and indexical conversational components of lesson analysis meetings that afford or constrain elementary preservice teachers’ incidences of professionally noticing students’ mathematical thinking.

Results:
Results indicated that the facilitator supported preservice teachers to identify and provide evidence of student thinking through direct questioning and probing, allowing free discussion, modeling interpretations of student thinking by connecting student actions to broader mathematical education learning theory, and gesturing to explain mathematical concepts. Conversational components that constrained professional noticing included discussion of pedagogical procedures and longer talk segments by the facilitator or classroom teacher.

Conclusions:
These findings demonstrate that lesson study can support preservice teachers' professional noticing. The lexical and indexical inclusions in the lesson study analysis meetings encouraged discussion and connections to students’ learning. As demonstrated by the facilitator in our study, we suggest that facilitators pay close attention to the prompts they pose and how they model analysis of student thinking during lesson study analysis meetings.