Writing a report/paper etc. - How to deal with citations that have poor English?

I've tried looking for suggestions on the internet to my question but haven't found any useful information.

I'm writing a paper and I'm quoting/citing various books, journals etc. However, I'm coming across of papers that are relevant to my paper that I would like to take quotes from, but were either originally written in another language and have been poorly translated, or were written with bad English to begin with.

Can I quote/cite the papers with corrected English or put the quote as-is? I'm worried if I don't correct the spelling mistakes/poor grammar etc. that the reputation/validity of my paper will be impacted. On the other hand I don't want any corrections I make in the quotes to be considered plagiarism. What should I do?