Legal Question in Business Law in Massachusetts

The facts of the situation would be paramount to a complete answer to such a question, but in general an otherwise competent adult who cannot read, but who signed an agreement would be responsible for the terms of the agreement. Facts that may change the answer may include if the person in good faith sought an oral explanation of the agreement and was given incorrect information - in general the law would rely on the basic elements of contract - there must be a "meeting of the minds" between the parties - in other words both parties must have had a mutual understanding of their intent to agree to something (the something being the elements of the contract -- the offer, the acceptance, the consideration, along with the terms, conditions, rights, and obligations).

Who the parties to the contract are would also be relevant as well as what each party knew about the other party. The law in some cases provides different standards when the parties to a contract do not have equal knowledge or expertise with respect to the subject matter of the contract or are not on relatively equal footing with respect to their ability to negotiate the terms of the contract. What each party knew about the other party may also be relevant.

If you feel that someone took advantage of a person or used unreasonable tactics to induce a person to unwittingly enter into an agreement you should encourage the person to speak with an attorney; you may also (depending on the facts) be able to receive assistance through the consumer protection division of the Attorney General's office or a private group like the Better Business Bureau.

In your outline you state "Is an illiterate person responsible for signing a contract after being mislead"

I would need far more detail as to the contract to be entered into, the mislead statement showing these facts

It will depend on the facts and without more information no intelligent answer can be given to you.