is it possible to patch photoshop to English if you bought another language version?
#1
Probably not. Although the majority of code will match, some terms for output are not, hence updates and patches will rupture at some point during install.
#2
It was possible in past releases to remove the language file from Photoshop thus making a non-English version mostly English. We certainly didn't recommend people do this, as it really was a mishmash of strings, and no longer support this in CS.
#3
In the past it was legal to install any software version (language) on your system, if you just have a valid licence for the software itself. So you maybe could install a copy of the Englisch version on your system using YOUR licence key.
Maybe you have a friend who is using the Englisch version of the software, who could give you a copy.
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I'M NOT A JUDGEMENT, SO I'M NOT SURE IF THIS IS STILL LEGAL.
#4