Hello. You have certainly had a tough time. This surgery is not easy.
I hope that you are being followed by a Speech Language Therapist. My husband has also had a total Glossectomy. It was the SLT who helped him with swallowing issues and learning to swallow. She was the one who introduced him first to liquids and then to soft purees.. The fact that you are coughing with swallowing fluids indicates that your swallow is not quite right and that you are aspirating liquid into the lungs - hence the cough. It will take time , be patient. Kris stopped using his feeding tube about 8 weeks after surgery. Remember too that everyone is different. If I was you, I would chase down that appointment with the speech therapist at your hospital.
Take care, Tammy

Caregiver/advocate to Husband Kris age 59@ diagnosis
DX Dec '10 SCC BOT T4aN2bM0 HPV+ve.Cisplatin x3 35 IMRT.
PET 6/11 clear.
R) level 2-4 neck dissection 8/1/11 to remove residual node - necrotic with NED
Feb '12 Ca back.. 3/8/12 total glossectomy/laryngectomy/bilat neck dissection/partial pharyngectomy etc. clear margins. All nodes negative for disease. PEG in.
March 2017 - 5 years disease free. Woohoo!