In this chapter, the authors aim to introduce a four-dimensional bilingual classroom observation protocol. They introduce a validated low-inference classroom observation instrument, and to use this instrument to describe time allocation of the teacher's pedagogical behavior in an English-medium instruction classroom with first year Chinese college students learning calculus. In addition to using classroom observation tools to observe language of instruction and classroom activities, some researchers integrate observation as part of teachers' professional development. The authors begin with their review of the literature with observation studies conducted in the United States, so as to gain insight into the type of observation instruments and teachers' pedagogy with English-Language Learners (ELLs) in that context. They describe a validated low-inference classroom observational instrument that was developed based on sound pedagogical theories with ELLs. The authors evaluate the alignment between the perceived and observed instructional time allocation.