Is there a possibility to make to "change language" field bigger or more visible?

Problem no 3

Is there a possibility to make to "change language" field more bigger or more visible?

Are you referring to the dropdown that shows up in the to right corner of the form? If you want to make the text bigger, try injecting the following code in your form: https://www.jotform.com/help/117-How-to-Inject-Custom-CSS-Codes 

.dd-placeholder {

    font-size: 20px !important;

}

Example: