The field of engineering is filled with immigrants. Silicon Valley is famously built from the creativity and hard work of immigrants around the world (China, India, Israel, and much more).
If English is your 2nd (or 3rd) language, only or mostly speaking your native language at work will hold back your career. Rachel talks about her misconception that communication skills weren't that important, and how to improve your speaking + writing.
If you want to get better at communication, check out our "Effective Communication" series.