Hey Christine - may be an East Coast thing- but typically a dietitian has the knowledge and education to identify that a Pt. is having a problem swallowing but can not diagnose the type of swallowing problem, identify contributing factors and most importantly can't treat the swallowing problem.
Treatment is key! Swallowing is so complex - and, depending on the problem, can be dangerous by causing respiratory complications or impeding adequate nutrition/hydration. What good have we done by identifying a weak swallow or a "lazy" epiglottis if we're not going to try to improve it through treatment?
If a dietitian tells you you have a swallowing problem then you'd best see an SLP for a full assessment and treatment! No disrespect to dietitians intended- they're awesome, but you don't want an SLP determining your dietary needs and you don't want a dietitian diagnosing (and treating) your swallowing problem.