timeline slicer for months only

ok,

now works formula:

=TEXT(DATEVALUE(M33);"mmmm rrrr")

when cell M33 contains "Luty 2016" ("Luty" is "February" in polish),

so it means that I have some settings set to polish. Where I can find it?
All Excel (menus, formulas, etc.) is in english.

Is any way to reach this if I have text in english like "January".

Still do not understand why you have added "1 " before month earlier