From a how did they swallow perspective, it is possible to swallow without the anterior portion of your tongue. The tongue itself is much bigger than you may suspect.

the back/base of your tongue (which likely remains) is the part that is imperative for keeping liquid and food in your oral cavity until you are ready to swallow. Once you do swallow, the back of your tongue is again the portion that initiates the swallow mechanisms to safely swallow.

So as long as you have the base of your tongue and take caution you could feasibly drink liquids and tolerate solids that don't need much chewing (think oatmeal).

I'm a Speech Pathologist and work in a skilled nursing facility with people who have swallow disorders every day. One patient had the anterior portion of his tongue removed secondary to cancer. He ate and drank a modified diet like a pro.