I have a samsung galaxy S4, as the title say, running with android, and i am french, therefore, the play store is in french, and the apps are also downloaded and installed in french, without any way in the settings in the play store or the application to change the language back to english, which i want, since the french translation on lots of applications is very poor (and also changes the font) It's very annoying and i've found no way, anywhere, to fix that
You can change the system language by goint to Settings > Language & Input > Language and selecting English (UK or USA, as you wish).
En français, ça se situe dans Paramètres > Langue et saisie > Langue.
But be aware : by the changing the system language, every applications will be changed to that language.
Some apps in Android like ( Playstore,Yahoo weather.. ) detect automatically your language from the settings of your phone; for example if your phone language is french the Playstore will be in french or if it's in english it will be in english..But there are also some apps which allow the user to change their language without changing your phone language; example Ted app,I have my phone in english and I use this app in french