My former chem lab professor offered to write me a LOR (totally out of the blue... I didn't even ask him). He is probably the professor who knows me best, so he could include info. that most other professors don't know. However, does not speak English very well. I know that his letter would have poor grammar in it. Is this something to consider? I'm kind of worried that the schools that I will be applying to wouldn't take his letter seriously (if I decide to have him write me a letter).