Is an agreement/contract valid if the person only speaks Spanish and the agreement/contract was in English? Me and my mom were partners in an llc and she signed over her 50% interests of the llc by...

Is an agreement/contract valid if the person only speaks Spanish and the agreement/contract was in English?
Me and my mom were partners in an llc and she signed over her 50% interests of the llc by just donating it to me being fully aware of what she was doing. The notarized agreement was in English but she speaks little to no English. Now she wants her percentage back over a personal matter so she is threatening to take me to court by claiming that the document was in English. Can she claim that she did not know what the document was thus making the agreement not valid? If so what what can I expect, she did sign more than one document at different stages relating to the same matter.