This is not related to translations.
Try hovering with your mouse over the position where the checkboxes should be (in front of each newsletter). If your mouse cursor changes from the arrow icon into a hand icon the checkbox is there, only not visible. You should be able to click it. In this case it is probably a css issue.
If the above doesn't work the checkboxes are not present for some reason. You can try to download and install Acymailing again. You will not loose any information. If that doesn't bring a solution either I suggest you raise a support ticket throug the contact form on www.acyba.com. Please grant backend and ftp access and login details as well as a link to this thread.