Here are all important links:
http://lmms.io/forum/viewtopic.php?f=1&t=4740
-A few rules and useful forum instructions
If you like to introduce yourself, to the community, go here:
http://lmms.io/forum/viewtopic.php?f=4&t=4480
Post a screen-shot of your \LMMS\data\locale -folder
If you do not have all the .qm files in \LMMS\data\locale that would be the result.
These .qm-files are installed by default so if they are missing you or a program have removed them, or some setting in windows/ virus-protection-software, prevented them from installation