*Strings not loaded:

In component/language/admin/en-GB.com_k2.ini line 24, 25, 26, 27
# LEADING=# Leading

# LINKS=# Links

# PRIMARY=# Primary

# SECONDARY=# Secondary

These strings will not load properly, as they begin with # wich comment them out in a ini file.

Solution, remove the # in the labels in component/admin/models/category.xml and change the strings in component/language/admin/en-GB.com_k2.ini to:

LEADING=# Leading

LINKS=# Links

PRIMARY=# Primary

SECONDARY=# Secondary

* Wrong strings in component/language/admin/en-GB.com_k2.ini

line 149 
SHOW BOTH INTROTEXT  FULLTEXT=Show both introtext  fulltext

should be

SHOW BOTH INTROTEXT & FULLTEXT=Show both introtext  fulltext

line 235
FEATURED' NOTICE (NEXT TO TITLE)='Featured' notice (next to title)

should be

'FEATURED' NOTICE (NEXT TO TITLE)='Featured' notice (next to title)

line 343
READ MORE...' LINK='Read more...' link

should be

'READ MORE...' LINK='Read more...' link

line 354, 355 (same string double!)
SAVE & NEW=Save & New

should be

SAVE & NEW=Save & New

line 362
SOCIAL BUTTON' LIKE SHARETHIS, ADDTHIS ETC.='Social button' like ShareThis, AddThis etc.

should be
'SOCIAL BUTTON' LIKE SHARETHIS, ADDTHIS ETC.='Social button' like ShareThis, AddThis etc.

line 383
TWEET THIS' LINK='Tweet this' link

should be
'TWEET THIS' LINK='Tweet this' link

* Missing language strings in component/language/admin/en-GB.com_k2.ini:

CREATED BY=Created by
ITEM ID=Item ID
MODIFIED BY=Modified by
NOTICE: PLEASE INSTALL JOOMLAWORKS ALLVIDEOS PLUGIN IF YOU WANT TO USE THE VIDEO FEATURES OF K2!=Notice: Please install JoomlaWorks AllVideos plugin if you want to use the video features of K2!
NOTICE: PLEASE INSTALL JOOMLAWORKS SIMPLE IMAGE GALLERY (FREE/PRO) PLUGIN IF YOU WANT TO USE THE IMAGE GALLERY FEATURES OF K2!=Notice: Please install JoomlaWorks Simple Image Gallery (Free/Pro) plugin if you want to use the image gallery features of K2!

* String not loaded caused by a space at the end:

in component/admin/views/extrafieldsgroup/view.html.php line 26
JToolBarHelper::title(JText::_('Add/Edit Extra Field Group '));

should be
JToolBarHelper::title(JText::_('Add/Edit Extra Field Group'));

(remove the space at the end of the string)

* Missing language strings in modules/mod_k2_content/en-GB.mod_k2_content.ini

FETCH ITEMS FROM CHILDREN CATEGORIES=Fetch items from children categories
HIGHEST RATED=Highest rated


* Missing language strings in modules/mod_k2_tools/en-GB.mod-k2_tools.ini

CALENDAR SETTINGS=Calendar Settings
CATEGORY FILTER=Category filter


* For the plugins are no languagefiles yet.


* Extended user info in frontend in profile.php and register.php strings not loaded:

The language strings extended info like Gender, URL, User Avatar etc. will try to fetch the strings from com_user.ini. So to translate we have to hack this file, since language overrides are not allowed in 1.5. This isn't convenient, so a better solution would be to load the com_k2.ini

add <?php JPlugin::loadLanguage( 'com_k2' ); ?> to component/site/templates/profile.php on line 59 and in component/site/templates/register.php on line 61

to also load the strings Male, Female:
add JPlugin::loadLanguage( 'com_k2' ); in plugins/k2.php before lines 85 and 135
Have to find out what can be used in k2.php for male and female

add these strings to component/language/site/en-GB.com_k2.ini
FEMALE=Female

MALE=Male

GENDER=Gender

UPLOAD NEW IMAGE TO REPLACE EXISTING AVATAR OR CHECK THIS BOX TO DELETE USER AVATAR=Upload new image to replace existing avatar or check this box to delete user avatar

URL=Url

USER AVATAR=User Avatar