Gedit spellchecker offers the system language as default. The suggestion is to offer the system language the first time Gedit is used, but from that point offer the last language selected for spellchecking.

- Users with only one language installed or spellchecking always the same language won't perceive any difference.

- Users with the system in one language but working often with documents in other language(s) will get a cleverer languiage guessing.

- This option would not be that useful for users spellchecking normalli language A but unsing once language B, they would need to select language A back. However, these extra clicks would save a lots of extra clicks from the previous group. And this group would find probably the behavikous sensible anyway.

I can tell from my own experience, having a system with Catalan locale but using spellchecking via Gedit specially in English (when posting here and there), where I need it more.