Quality of English in a college recommendation letter Does the quality of English in a letter of recommendation matter? Should it be really good or just average English with occasional mistakes suffice as long as the meaning is clear? Is a perfectly written letter with no grammatical mistakes better then a letter with few mistakes without flowery language if the points mentioned in both are the same?
The people reading a recommendation letter are interested in the following two things:


What is the assessment that the recommender makes of your skills and potential?
How much should they trust the recommender's assessment?


The style and errors of the recommender primarily speak to the second point.  It is hard to see how an occasional "normal" mistake will make a significant difference in how your or the letter-writer are perceived.  Likewise, if the writer is not a native English speaker, but makes mild typical grammatical errors that do not impede the sense of the document, it is just part of the normal "friction" of cross-cultural scientific communication and should not be a problem.

If, however, the mistakes are frequent and significant, then it may undermine the credibility of the recommendation.  Frequent or severe mistakes can make a reader think either that the recommender doesn't really care about this letter or that they are sloppy and perhaps don't have very good judgement to begin with.  Fairly or not, this can also apply to foreign-language issues, since a professor who knows their English is not good can get proof-reading help from any number of sources.