Which is my second point: citizens will have to follow and vote on the law of their country, including international treaties, without understanding them since they are not written in their language.
In addition, I can present the case of France, where judges must disregard laws that contradict treaties (the hierarchy of norms being Constitution > Treaties > Laws > Executive orders). Therefore treaties, even with no national law to implement them, have a direct effects on the law.
Once a treaty enters into effect, a nation is bound by the terms of the treaty even if they do not have implementing laws. However, in many cases treaties don't have any consequences if signatories don't pass implementing laws (see, e.g, the Kyoto Protocol).