Here is the Lithuanian Language files for IPS 4.0.X. As I do not speak/read/write this language either, I don't know how accurate this version of the language is.
It is in the form of a .zip file
IP.Board Language Packs
IPS 4.0.X Lithuanian Language 1.1
Submitted by guntherbb, 12-05-2015, 01:57 AM, Thread ID: 3690
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