Hi Steve .. my swallowing and speech (dysphagia and dysarthria) & also with severe neck fibrosis did not or was not evident until 15 years ago. And, because after the treatment and recovered - I had no issues with swallowing (except that I had to have liquid to help in taking the food down), and or speech.
Now - I wish I had done my dysphagia exercises back when I had finished treatment. Now I can only do my best with daily exercises - and hope to prevent late effects from getting worse!