Ok, i made the iMacros script for you.
Actually i made it for myself a while back for changing usernames, there's only one line difference compared to that.
HTML:
TAB T=1
TAB CLOSEALLOTHERS
SET !ERRORIGNORE NO
SET !DATASOURCE_DELIMITER ;
SET !DATASOURCE c:\accounts.csv
SET !LOOP 1
SET !DATASOURCE_LINE {{!LOOP}}
CLEAR
PROXY ADDRESS={{!COL3}}:{{!COL4}}
SET !ENCRYPTION NO
ONLOGIN USER={{!COL5}} PASSWORD={{!COL6}}
URL GOTO=https://twitter.com/settings/account
TAG POS=2 TYPE=INPUT:TEXT FORM=ACTION:https://twitter.com/sessions ATTR=NAME:session[username_or_email] CONTENT={{!COL1}}
SET !ENCRYPTION NO
TAG POS=2 TYPE=INPUT:PASSWORD FORM=ACTION:https://twitter.com/sessions ATTR=NAME:session[password] CONTENT={{!COL2}}
TAG POS=1 TYPE=BUTTON:SUBMIT FORM=ACTION:https://twitter.com/sessions ATTR=TXT:Log<SP>in
WAIT SECONDS=1
TAG POS=1 TYPE=SELECT FORM=ACTION:https://twitter.com/settings/accounts/update ATTR=NAME:user[lang] CONTENT=%en
TAG POS=1 TYPE=BUTTON:SUBMIT FORM=ACTION:https://twitter.com/settings/accounts/update ATTR=ID:settings_save
TAG POS=2 TYPE=INPUT:PASSWORD FORM=ACTION:https://twitter.com/settings/accounts/update ATTR=NAME:auth_password CONTENT={{!COL2}}
TAG POS=1 TYPE=BUTTON:SUBMIT FORM=ACTION:https://twitter.com/settings/accounts/update ATTR=ID:save_password
WAIT SECONDS=1
CLEAR
Put the accounts.csv into the root of your c: drive or alter the file path in the macro (5th line).
The format of the .csv should be: TwitterUsername;TwitterPassword;ProxyIP;ProxyPort ;ProxyUsername;ProxyPassword. One account per line.
Play the macro in loop. Loop count = the amount of line your .csv has = the amount of accounts you want to change the language on.
Use it with the Firefox iMacros addon, the standalone browser is sluggish and buggy sometimes.
