In my 30 years of teaching chemistry, I have never had one student who wanted me to explain course material in Spanish--except this summer term. Three students in my current biochemistry class are from my former mission area, Peru and Ecuador. They feel more comfortable conversing in Spanish, and one of them frequently comes to my office for Spanish explanations of what we've covered in class.
In fact, I just barely finished a 1½-hour biochemistry lecture/help session in Spanish with two of these Spanish-speaking students, Bertha and Lorena, both from Ecuador. We covered protein structure, calculation of net charge on peptides, determination of isoelectric point, interactions between biomolecules, and other subjects that will appear on the next exam. I think I learned as much Spanish as they did biochemistry.
I know these sessions are absolutely wonderful opportunities for me to push myself in Spanish and to become more comfortable in speaking Spanish in a wide variety of different situations.
What a great blessing I've received this school term as I prepare for my mission in Peru!