you can use any of those OS X upgrades as they are Tied to the original owners Apple ID. Click the Language and region icon in the System Preferences window. In the upper-left corner of the screen, click the Apple icon to open the Apple menu and choose System Preferences.
HOW TO CHANGE MACBOOK LANGUAGE TO ENGLISH MAC
This is the only way to get all data from the previous owner off that system along with any OS X upgrades they might of done. Consequently, you need to go into your Mac language settings to change the language displayed in Safari. Once that finished you will be presented with the system setup pages where you chose a language and the like. Pick the desired language from the populated list and click Add. Once in Language and Region, add a new language by clicking on the + icon. Once in System Preferences, click on Language and Region. The original version of OS X the system shipped with will be downloaded from the internet and installed on your Air. Change System Language: Click on the Apple Menu on the top left of the screen.
HOW TO CHANGE MACBOOK LANGUAGE TO ENGLISH MAC OS
Once that is done, formatted Mac OS Extended (Journaled) with a Partition Table of GUID (that is found under the Options button) exit DU and select "Reinstall Mac OS X". From the screen that comes up you have to Repartition the drive as One Partition by selecting One Partition from the Partition layout area on the Partition tab of disk Utility.
So have a good working internet connetion and know your router WiFi password, you will need it. If the language you want is not in the list, click the ‘+’ and choose it from the list. If the language you want to add is in the Preferred languages list, select it. You can add a language by clicking the Add button, selecting one or more languages in the list, and then clicking the Add button. You can click General under the General tab. My preferences for the language and region I am using.
Click on the Apple menu and choose System Preferences. Select Language & Region from the Apple menu > System Preferences on your Mac. That will boot the system from the Apple servers on the internet. The first step is to change the system language. At startup hold down the Command + Option/Alt + r keys and keep them held down until you seea globe on the screen.