CHANGING YOUR PERSONAL LANGUAGE:
To change the language for your own login:
1. Click on:
a. (Classic) Setup | Personal Setup | My Personal Information | Edit
b. (Classic; Improved Setup) Your name | My Settings | Personal | Language & Time Zone
c. (Lightning Experience) Your Avatar | Settings | Language & Time Zone
2. Change the Language drop-down to the language you want.
3. You may also want to modify your Locale setting to control the formatting of numbers, dates, and phone numbers.
4. Click "Save".
You should now see the Salesforce text in the desired language.
NOTE: Some items are not automatically switched to the new language because they are global data for your organization. Your administrator will need to change those items for example: Recently Viewed, Recently Modified and Recently Created.
STANDARDIZING ON ONE LANGUAGE FOR YOUR ORGANIZATION:
If you want to standardize your entire company on a particular language and locale, an administrator will need to modify or translate some global data for the organization:
5. Click on Setup | Administration Setup | Company Profile | Company Information | Edit and change the Default Language, Default Locale, and Currency Locale. All new users will inherit these Language and Locale settings.
6. Click on Setup | Administration Setup | Translation Workbench to translate the values for several setup components, eg Button and Link labels, Record Types, Address Country/State, also all of your organization's picklists, both the standard picklists and the custom ones, eg:
a. Events (Home tab)
b. Tasks (Home tab)
k. Partner Role (Account tab)
l. Contact Role (Opportunities tab)
7. Click "Edit This Message" in the sidebar of the Home page to translate any Messages and Useful Links.
8. Click on: Setup | Administration Templates | Communication Templates | Email Templates to translate your organization's public email templates.
9. On the tab overview pages, translate the names of the public list views for all record types:
j. Activities (Click the list view icon under the calendar on the Home tab)
k. Users (Setup | Administration Setup | Manage Users | Users).
10. Translate any other shared items that you have created for your organization, such as:
a. Public Reports
b. Public Mail Merge Templates
c. Custom Fields
d. Lead Queue Names
e. Case Queue Names
f. Custom Links
11. Enterprise Edition administrators may also want to change the names of the standard page layouts.
NOTE: These modifications will apply to all users in your organization even if a particular user does not switch his or her personal Language to the target language.
NOTE: Some global items cannot be changed. These are:
12. Standard mail merge templates
13. Default tasks assigned to new users
14. Names of the standard profiles