Are the sentences below grammatically correct? Do they make sense? If not, could you correct them?
When I casually turned on the TV and watched Princess Kako giving a speach in English,
I found her speaking skills were not as fluent as returnee students'.
However, I love her English because such students sound like native English speakers, not Japanese.
Do you think I am partial to her?https://www.youtube.com/watch?v=_wpdx-5iDNw
This is her speach.

Question

Are the sentences below grammatically correct? Do they make sense? If not, could you correct them?
When I casually turned on the TV and watched Princess Kako giving a speach in English, 
 I found her speaking skills were not as fluent as returnee students'. 
 However, I love her English because such students sound like native English speakers, not Japanese. 
 Do you think I am partial to her?https://www.youtube.com/watch?v=_wpdx-5iDNw
This is her speach.

Answer

All perfect, though the subtlety of the genitive "students'" might be lost on many native speakers, who might erroneously consider it a mistake; "those of returnee students" is safer.