Another possibility would be to phrase it as a request for clarification:
"I'm not entirely sure of what you mean. Would it be correct to say 'X?'"
"In other words, 'Y?'"
The speaker might realize that s/he did not use the most-correct phrase to convey what s/he meant to say, but here the correction has been offered graciously.
Also, consider if the way that the speaker did put it was "good 'enuf." If it's clear-enough what the speaker meant to say, maybe "let it ride."
The key is to judge the speaker's personality and temperament, and above all not to appear patronizing or insulting.
If you are the person's superior, remember that the person might not reveal to you any displeasure or discomfort.
In Spanish culture (and, many European cultures, vs. USA), there is a whirlwind of implied cultural context. It is imperative that you be aware of how any foreigner would interpret what you say, in the context of his or her culture, not your own. It is imperative, also, that you be sensitive to the possibility of "I shall not let you hear me scream."
Consider taking this person privately aside, and ask him or her what s/he would honestly prefer. Maybe s/he welcomes the instruction. Maybe, s/he is mortified and humiliated. In private, s/he may be honest.
"Fragile: Contains a genuine human being."