Hi, we have been through this. Some thing similar.
2 1/2 years ago Kris had a total Laryngectomy as well as a total Glossectomy. So he lost both his voice box and his entire tongue.
As you sister has already had a laryngectomy her Stoma will be well formed and her airway secure. She won't need a trachy tube as her Trache is well formed.
Kris communicated initially with a whiteboard, then moved quickly onto the IPad. He uses an app called " Speakit" it is free to download.
There is also something called a Boogieboard , you could check it out.
How will your sister be fed? Are they just going to use a Naso gastric tube for feeding,? Have they discussed a PEG tube. I would think that they will get her swallowing pretty quickly and of course as she has had a laryngectomy aspiration will not be an issue. It will just be a matter of the SLT working with her to get her swallowing. Kris, with no tongue, started swallowing after 2 weeks and swallows all his nutrition with no problems.
She will be fine. Lots of love and encouragement from her family will get her through. Always be positive.
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!